AP Practice Questions v12-beta

v12-beta · 120题·跨10科CED Unit topic-code锚点 · Syllabus v3双向对齐

Sample Questions

Group 1 · Calculus & Math (20 questions)

Q1 【CALC-U64】 · AP Calculus BC · Integration · Easy

Evaluate ∫(2x + 3) dx.

Answer: A) x² + 3x + C. ∫2x dx = x², ∫3 dx = 3x, + C.
Q4 【CALC-U11】 · AP Calculus AB · Limits · Easy

Evaluate: lim(x→2) (x² − 4) / (x − 2).

Answer: C) 4. Factor: (x − 2)(x + 2) / (x − 2) = x + 2. At x = 2: 2 + 2 = 4.
Q5 【CALC-U101】 · AP Calculus BC · Series · Hard

Determine if the series Σ(n = 1 to ∞) 1/n² converges.

Answer: C) Converges to π²/6. This is the Basel problem; the series converges to π²/6 ≈ 1.645.
Q9 【STAT-U41】 · AP Statistics · Probability · Easy

A fair six-sided die is rolled. What is the probability of rolling a number greater than 4?

Answer: B) 1/3. Numbers > 4 are 5 and 6, so 2/6 = 1/3.
Q11 【CALC-U21】 · AP Calculus AB · Differentiation · Easy

Find f'(x) if f(x) = 5x³.

Answer: A) 15x². Power rule: 3 × 5x² = 15x².
Q12 【CALC-U11】 · AP Calculus AB · Limits · Medium

Evaluate: lim(x→0) sin(x)/x.

Answer: B) 1. This is a fundamental limit.
Q13 【CALC-U64】 · AP Calculus BC · Integration · Medium

Evaluate ∫(1/x) dx.

Answer: B) ln|x| + C.
Q14 【CALC-U42】 · AP Calculus AB · Applications · Hard

If the position function is s(t) = t³ − 6t² + 9t, at what time(s) is the velocity zero?

Answer: C) t = 1 and t = 3. v(t) = 3t² − 12t + 9 = 3(t − 1)(t − 3) = 0, so t = 1 and t = 3.
Q21 【CALC-U31】 · AP Calculus BC · Chain Rule · Easy

Find dy/dx if y = (3x + 1)⁴.

Answer: B) 12(3x + 1)³. Chain rule: 4(3x + 1)³ × d/dx(3x + 1) = 4(3x + 1)³ × 3 = 12(3x + 1)³.
Q22 【CALC-U32】 · AP Calculus BC · Product Rule · Medium

Find dy/dx if y = x² · sin(x).

Answer: B) 2x · sin(x) + x² · cos(x). Product rule: (fg)' = f'g + fg', with f = x², g = sin(x).
Q23 【CALC-U33】 · AP Calculus BC · Quotient Rule · Medium

Find dy/dx if y = (x² + 1) / (x − 1).

Answer: A) [2x(x − 1) − (x² + 1)] / (x − 1)². Quotient rule: (f/g)' = (f'g − fg') / g².
Q24 【CALC-U61】 · AP Calculus AB · Riemann Sums · Medium

Approximate ∫₀² x² dx using a right Riemann sum with n = 4 subintervals.

Answer: B) 3.75. Δx = 0.5. Heights at x = 0.5, 1, 1.5, 2 are 0.25, 1, 2.25, 4. Sum = 0.5 × (0.25 + 1 + 2.25 + 4) = 0.5 × 7.5 = 3.75.
Q25 【CALC-U102】 · AP Calculus BC · Taylor Series · Hard

What are the first three non-zero terms of the Maclaurin series for eˣ?

Answer: A) 1 + x + x²/2. eˣ = Σ xⁿ/n! = 1 + x + x²/2! + x³/3! + ...
Q26 【CALC-U41】 · AP Calculus AB · Related Rates · Hard

A spherical balloon's radius increases at 2 cm/s. When r = 5 cm, what is dV/dt? (V = 4/3 πr³)

Answer: D) 200π cm³/s. dV/dt = 4πr² · dr/dt = 4π(25)(2) = 200π.
Q27 【CALC-U51】 · AP Calculus AB · Optimization · Hard

Find the dimensions of the rectangle with maximum area and perimeter 20.

Answer: A) 5 × 5. With perimeter 20 (so length + width = 10), max area A = w(10 − w) is maximized at w = 5, giving a 5 × 5 square (area 25).
Q28 【CALC-U72】 · AP Calculus BC · Slope Fields · Medium

A slope field has horizontal line segments (slope 0) at every point along the x-axis (y = 0). Which differential equation matches?

Answer: B) dy/dx = y. When y = 0, slope = 0; segments are horizontal everywhere on the x-axis.
Q29 【CALC-U92】 · AP Calculus BC · Parametric Derivatives · Hard

If x = t² and y = t³, find dy/dx at t = 2.

Answer: B) 3. dy/dx = (dy/dt) / (dx/dt) = 3t² / 2t = 3t/2. At t = 2: 3(2)/2 = 3.
Q30 【CALC-U93】 · AP Calculus BC · Polar Area · Hard

Find the area enclosed by the polar curve r = 2 (a circle of radius 2).

Answer: B) 4π. A = ½ ∫₀²π r² dθ = ½ ∫₀²π 4 dθ = ½ × 4 × 2π = 4π.
Q31 【CALC-U66】 · AP Calculus BC · Improper Integrals · Hard

Evaluate ∫₁^∞ 1/x² dx.

Answer: B) 1. ∫₁^∞ x⁻² dx = [−x⁻¹]₁^∞ = 0 − (−1) = 1.
Q32 【CALC-U74】 · AP Calculus BC · Logistic Growth · Medium

In logistic growth, the population grows fastest when:

Answer: B) Population equals half the carrying capacity. The inflection point of the logistic curve occurs at K/2, where growth rate is maximal.

Group 2 · Science (16 questions)

Q2 【CHEM-U41】 · AP Chemistry · Stoichiometry · Medium

How many moles of H₂O are produced when 2 moles of H₂ react with excess O₂? 2H₂ + O₂ → 2H₂O

Answer: B) 2. The balanced equation shows 2 mol H₂ produces 2 mol H₂O, so the ratio is 1:1.
Q6 【CHEM-U31】 · AP Chemistry · Gas Laws · Medium

At STP, what volume does 2 moles of an ideal gas occupy? (Vm = 22.4 L/mol at STP)

Answer: C) 44.8 L. V = n × Vm = 2 × 22.4 = 44.8 L.
Q7 【BIO-U21】 · AP Biology · Cell Division · Medium

During which phase of mitosis do sister chromatids separate?

Answer: C) Anaphase. During anaphase, sister chromatids are pulled apart toward opposite poles.
Q15 【CHEM-U42】 · AP Chemistry · Molar Mass · Easy

What is the molar mass of H₂O? (H = 1, O = 16)

Answer: C) 18 g/mol. 2(1) + 16 = 18.
Q16 【BIO-U51】 · AP Biology · DNA Replication · Medium

During which process does DNA replicate?

Answer: C) S phase. DNA replication occurs during S phase of interphase.
Q17 【CHEM-U43】 · AP Chemistry · Equations · Hard

Balance: __C₃H₈ + __O₂ → __CO₂ + __H₂O.

Answer: A) 1, 5, 3, 4. C₃H₈ + 5O₂ → 3CO₂ + 4H₂O.
Q33 【CHEM-U81】 · AP Chemistry · Acid-Base Titration · Medium

In a titration, 25 mL of HCl requires 20 mL of 0.1 M NaOH for neutralization. What is [HCl]?

Answer: B) 0.08 M. M₁V₁ = M₂V₂ → M₁ × 25 = 0.1 × 20 → M₁ = 2/25 = 0.08 M.
Q34 【CHEM-U82】 · AP Chemistry · Buffers · Hard

Which combination forms a buffer solution?

Answer: C) CH₃COOH and CH₃COONa. A buffer requires a weak acid (CH₃COOH) and its conjugate base (CH₃COO⁻ from sodium acetate). Strong acids/bases do not form buffers.
Q35 【CHEM-U62】 · AP Chemistry · Thermodynamics · Hard

For a reaction to be spontaneous at all temperatures, which must be true? (ΔG = ΔH − TΔS)

Answer: C) ΔH < 0, ΔS > 0. With ΔH negative and ΔS positive, ΔG = ΔH − TΔS is always negative, so the reaction is always spontaneous.
Q36 【CHEM-U91】 · AP Chemistry · Electrochemistry · Hard

In a galvanic cell, oxidation occurs at the:

Answer: B) Anode. Oxidation always occurs at the anode (in both galvanic and electrolytic cells); electrons flow from anode to cathode.
Q37 【BIO-U71】 · AP Biology · Natural Selection · Medium

Industrial melanism in peppered moths (Biston betularia) is a classic example of:

Answer: B) Natural selection. Darker moths had higher fitness in polluted (soot-darkened) areas, an example of directional selection.
Q38 【BIO-U72】 · AP Biology · Genetic Drift · Medium

The bottleneck effect (a population shrinking dramatically) is an example of:

Answer: B) Genetic drift. The bottleneck effect causes random changes in allele frequencies due to a sharp population reduction.
Q39 【BIO-U81】 · AP Biology · Ecology · Easy

Which biome is characterized by permafrost and low-growing vegetation?

Answer: B) Tundra. Tundra has permafrost, short growing seasons, and low-growing plants adapted to cold.
Q40 【BIO-U41】 · AP Biology · Cell Signaling · Medium

A signal molecule that binds to a receptor on the cell surface is called a:

Answer: C) Ligand. A ligand is a signaling molecule that binds to a specific receptor, often triggering a response inside the cell.
Q41 【BIO-U62】 · AP Biology · Gene Regulation · Hard

The lac operon in E. coli is induced (turned on) in the presence of:

Answer: B) Lactose. Lactose binds to the repressor, causing it to release the operator and allowing transcription of lactose-metabolism genes.
Q42 【BIO-U64】 · AP Biology · Lab Techniques · Medium

Which technique is used to amplify a specific segment of DNA?

Answer: B) PCR. The Polymerase Chain Reaction amplifies specific DNA sequences exponentially through cycles of denaturation, annealing, and extension.

Group 3 · History & CS (14 questions)

Q3 【HIST-U13】 · AP US History · Period 3 · Medium

Which event directly led to the writing of the Federalist Papers?

Answer: B). The Federalist Papers were written to persuade states to ratify the Constitution.
Q8 【HIST-U14】 · AP US History · Period 4 · Medium

The Monroe Doctrine (1823) declared that:

Answer: B). The Monroe Doctrine stated that the Western Hemisphere was no longer open for European colonization.
Q10 【CSA-U51】 · AP Computer Science A · Arrays · Medium

What is the output of: int[] arr = {3, 1, 4, 1, 5}; System.out.println(arr[2]);

Answer: C) 4. Arrays are 0-indexed, so arr[2] is the third element: 4.
Q18 【HIST-U15】 · AP US History · Civil War · Medium

The Emancipation Proclamation (1863) declared freedom for enslaved people in:

Answer: B) Confederate states only.
Q19 【CSA-U11】 · AP Computer Science A · Types · Easy

What does 'int' represent in Java?

Answer: B) An integer.
Q20 【STAT-U42】 · AP Statistics · Probability · Medium

If P(A) = 0.3 and P(B) = 0.4 and A and B are independent, what is P(A and B)?

Answer: B) 0.12. P(A ∩ B) = P(A) × P(B) = 0.3 × 0.4 = 0.12.
Q43 【HIST-U16】 · AP US History · Reconstruction · Medium

The 13th Amendment to the US Constitution (1865):

Answer: B) Abolished slavery and involuntary servitude. (Citizenship was the 14th; voting rights regardless of race were the 15th; women's suffrage was the 19th.)
Q44 【HIST-U16】 · AP US History · Gilded Age · Medium

The Gilded Age (late 1800s) was characterized by:

Answer: B) Industrial expansion and political corruption. The era saw rapid industrialization, the rise of robber barons, and widespread political graft, beneath a "gilded" surface.
Q45 【HIST-U17】 · AP US History · Progressive Era · Medium

Which was a major goal of the Progressive Era (1890s–1920s)?

Answer: C) Reforming government and reducing corruption. Progressives sought political, social, and economic reforms including direct primaries, antitrust laws, and women's suffrage.
Q46 【HIST-U18】 · AP US History · Cold War · Hard

The US policy of containment during the Cold War aimed to:

Answer: B) Prevent the spread of communism. Containment, articulated by George Kennan in the "Long Telegram," sought to stop communism from expanding beyond its existing borders.
Q47 【HIST-U19】 · AP US History · Civil Rights · Medium

Brown v. Board of Education (1954) ruled that:

Answer: A) Segregation in public schools was unconstitutional. The unanimous decision overturned the "separate but equal" doctrine of Plessy v. Ferguson in public education.
Q48 【CSA-U101】 · AP Computer Science A · Recursion · Hard

What is the output of: public static int f(int n) { if (n == 0) return 1; return n * f(n − 1); } f(4)?

Answer: C) 24. The method computes 4! = 4 × 3 × 2 × 1 = 24 recursively.
Q49 【CSA-U61】 · AP Computer Science A · Linked Lists · Medium

What is the main advantage of a linked list over an array?

Answer: B) Easier insertion/deletion at a known node. Linked lists allow O(1) insertion/deletion when the node position is known, since only pointers are updated (no shifting). Arrays allow O(1) random access.
Q50 【STAT-U61】 · AP Statistics · Hypothesis Testing · Hard

A hypothesis test yields a p-value of 0.03 at significance level α = 0.05. The correct conclusion is to:

Answer: B) Reject H₀. Since p < α (0.03 < 0.05), there is sufficient evidence to reject the null hypothesis at the 0.05 level. We never "accept" H₀; we only fail to reject it.

Group 4 · Calculus & Math Extension (25 questions)

Q51 【CALC-U13】 · AP Calculus BC · Squeeze Theorem · Medium

Use the squeeze theorem to find lim(x→0) x² sin(1/x).

Answer: A) 0. Since −1 ≤ sin(1/x) ≤ 1, we have −x² ≤ x² sin(1/x) ≤ x². Both bounds → 0 as x → 0, so the limit is 0.
Q52 【CALC-U12】 · AP Calculus AB · Continuity · Medium

For what value of k is f(x) = { (x² − 1)/(x − 1) if x ≠ 1; k if x = 1 } continuous at x = 1?

Answer: C) 2. lim(x→1) (x² − 1)/(x − 1) = lim(x→1) (x + 1) = 2. For continuity, k must equal this limit.
Q53 【CALC-U22】 · AP Calculus AB · Trig Derivatives · Easy

Find d/dx [cos(x)].

Answer: B) −sin(x). The derivative of cos(x) is −sin(x).
Q54 【CALC-U65】 · AP Calculus BC · U-Substitution · Medium

Evaluate ∫ 2x · (x² + 1)⁵ dx.

Answer: A) (x² + 1)⁶ / 6 + C. Let u = x² + 1, du = 2x dx. ∫ u⁵ du = u⁶/6 + C = (x² + 1)⁶/6 + C.
Q55 【CALC-U81】 · AP Calculus AB · Area Between Curves · Medium

Find the area between y = x and y = x² from x = 0 to x = 1.

Answer: A) 1/6. ∫₀¹ (x − x²) dx = [x²/2 − x³/3]₀¹ = 1/2 − 1/3 = 1/6.
Q56 【CALC-U82】 · AP Calculus BC · Volume of Revolution · Hard

Find the volume when y = √x from x = 0 to x = 4 is revolved about the x-axis.

Answer: A) 8π. V = π ∫₀⁴ (√x)² dx = π ∫₀⁴ x dx = π × 8 = 8π.
Q57 【CALC-U71】 · AP Calculus AB · Separable DEs · Medium

Solve dy/dx = y, with y(0) = 2.

Answer: A) y = 2eˣ. Separating: dy/y = dx → ln|y| = x + C → y = Aeˣ. Using y(0) = 2 gives A = 2.
Q58 【CALC-U104】 · AP Calculus BC · Geometric Series · Hard

For what values of r does Σ(n=0 to ∞) rⁿ converge?

Answer: C) |r| < 1. A geometric series converges if and only if the common ratio has absolute value less than 1, summing to 1/(1 − r).
Q59 【CALC-U91】 · AP Calculus BC · Parametric Arc Length · Hard

For the parametric curve x = t², y = t³, set up the arc length integral from t = 0 to t = 2.

Answer: A) ∫₀² √(4t² + 9t⁴) dt. Arc length = ∫ √((dx/dt)² + (dy/dt)²) dt = ∫ √(4t² + 9t⁴) dt.
Q60 【CALC-U108】 · AP Calculus BC · Sequence Convergence · Medium

Does the sequence aₙ = (−1)ⁿ / n converge?

Answer: A) Yes, to 0. Although the sign alternates, the magnitude 1/n → 0, so the sequence converges to 0.
Q61 【CALC-U103】 · AP Calculus BC · Maclaurin Series · Hard

What is the Maclaurin series for sin(x)?

Answer: B) x − x³/3! + x⁵/5! − .... sin(x) = Σ(−1)ⁿ x^(2n+1) / (2n+1)!.
Q62 【CALC-U105】 · AP Calculus BC · Ratio Test · Hard

Using the ratio test on Σ(n=1 to ∞) n! / 10ⁿ, the series:

Answer: B) Diverges (ratio > 1). Ratio = (n+1)! / 10^(n+1) × 10ⁿ / n! = (n+1)/10 → ∞ as n → ∞, so the series diverges.
Q63 【CALC-U106】 · AP Calculus BC · Integral Test · Hard

Use the integral test on Σ(n=1 to ∞) 1/(n² + 1). The series:

Answer: B) Converges. ∫₁^∞ dx/(x² + 1) = [arctan x]₁^∞ = π/2 − π/4 = π/4 (finite), so the series converges by the integral test.
Q64 【CALC-U107】 · AP Calculus BC · Comparison Test · Hard

Does Σ(n=1 to ∞) 1/(n² + n) converge?

Answer: A) Yes, by comparison with Σ 1/n². Since 1/(n² + n) < 1/n² for all n ≥ 1, and Σ 1/n² converges (p-series, p > 1), the series converges by direct comparison.
Q65 【CALC-U109】 · AP Calculus BC · Power Series · Hard

What is the radius of convergence of Σ(n=0 to ∞) xⁿ / n! ?

Answer: D) ∞. Using the ratio test: |a(n+1)/aₙ| = |x| / (n + 1) → 0 < 1 for all x, so the series converges for all real x.
Q66 【CALC-U83】 · AP Calculus BC · Arc Length · Hard

Set up the arc length integral of y = x^(3/2) from x = 0 to x = 4.

Answer: D) All of the above (equivalent forms). y' = (3/2)x^(1/2), so 1 + (y')² = 1 + (9/4)x. The integral is ∫₀⁴ √(1 + 9x/4) dx.
Q67 【CALC-U84】 · AP Calculus BC · Surface Area · Hard

The surface area formula for rotating y = f(x) from a to b about the x-axis is:

Answer: A) 2π ∫ y · √(1 + (dy/dx)²) dx. Surface area = 2π ∫ y ds, where ds = √(1 + (dy/dx)²) dx is the arc length element.
Q68 【CALC-U74】 · AP Calculus BC · Logistic Growth · Medium

A population grows logistically with carrying capacity K. As t → ∞, the population size approaches:

Answer: C) K. The logistic curve approaches the carrying capacity K asymptotically as t → ∞.
Q69 【CALC-U73】 · AP Calculus AB · Euler's Method · Medium

Given dy/dx = y with y(0) = 1, use Euler's method with step h = 0.1 to estimate y(0.2).

Answer: A) 1.21. Step 1: y(0.1) ≈ 1 + 0.1 × 1 = 1.1. Step 2: y(0.2) ≈ 1.1 + 0.1 × 1.1 = 1.21.
Q70 【CALC-U72】 · AP Calculus BC · Slope Fields · Medium

A slope field has all segments with slope 1 (regardless of x, y). Which DE matches?

Answer: A) dy/dx = 1. The slope is constant (1) at every point, matching dy/dx = 1.
Q71 【CALC-U62】 · AP Calculus AB · Midpoint Riemann Sum · Medium

Approximate ∫₀² x² dx using a midpoint Riemann sum with n = 4 subintervals.

Answer: B) 2.625. Δx = 0.5. Midpoints: 0.25, 0.75, 1.25, 1.75. Sum = 0.5 × (0.0625 + 0.5625 + 1.5625 + 3.0625) = 0.5 × 5.25 = 2.625.
Q72 【CALC-U63】 · AP Calculus AB · Fundamental Theorem · Easy

If F(x) = ∫₀ˣ f(t) dt, then F'(x) = ?

Answer: B) f(x). By the Fundamental Theorem of Calculus (Part 1), the derivative of an integral function is the integrand evaluated at the upper limit.
Q73 【CALC-U52】 · AP Calculus AB · Mean Value Theorem · Medium

For f(x) = x² on [1, 3], what value of c satisfies the MVT?

Answer: B) 2. Average rate = (f(3) − f(1)) / (3 − 1) = (9 − 1) / 2 = 4. f'(x) = 2x = 4 → x = 2.
Q74 【CALC-U41】 · AP Calculus AB · Related Rates · Hard

A 10 ft ladder leans against a wall. The bottom slides away at 2 ft/s. When the bottom is 6 ft from the wall, how fast is the top sliding down?

Answer: A) 1.5 ft/s. x² + y² = 100. When x = 6, y = 8. Differentiate: 2x · dx/dt + 2y · dy/dt = 0 → 12(2) + 16 · dy/dt = 0 → dy/dt = −24/16 = −1.5 ft/s.
Q75 【CALC-U51】 · AP Calculus AB · Optimization · Hard

An open-top box is made from a 12 × 12 inch square by cutting equal squares from corners and folding. What corner size maximizes volume?

Answer: B) 2 inches. V = x(12 − 2x)². dV/dx = (12 − 2x)² − 4x(12 − 2x) = (12 − 2x)(12 − 6x). Setting dV/dx = 0 gives x = 2 (the valid interior critical point).

Group 5 · Science Extension (25 questions)

Q76 【CHEM-U11】 · AP Chemistry · Quantum Numbers · Medium

Which set of quantum numbers is NOT valid?

Answer: C) n = 3, ℓ = 3, mℓ = 0, ms = +1/2. ℓ must be in the range 0 to n − 1, so for n = 3, ℓ can only be 0, 1, or 2.
Q77 【CHEM-U21】 · AP Chemistry · Electronegativity · Medium

Which element has the highest electronegativity?

Answer: D) F. Fluorine has the highest electronegativity (4.0 on the Pauling scale); it increases toward the top-right of the periodic table (excluding noble gases).
Q78 【CHEM-U22】 · AP Chemistry · Hybridization · Medium

What is the hybridization of the central atom in CH₄?

Answer: C) sp³. Carbon forms 4 single bonds (tetrahedral geometry, 109.5°), requiring sp³ hybridization.
Q79 【CHEM-U33】 · AP Chemistry · Hydrogen Bonding · Medium

Which substance exhibits hydrogen bonding between molecules?

Answer: C) NH₃. Hydrogen bonding requires H bonded to N, O, or F. NH₃ has N−H bonds, allowing strong dipole-dipole hydrogen bonds.
Q80 【CHEM-U61】 · AP Chemistry · Hess's Law · Medium

Given: (1) C + O₂ → CO₂, ΔH = −394 kJ; (2) 2CO + O₂ → 2CO₂, ΔH = −566 kJ. Find ΔH for 2C + O₂ → 2CO.

Answer: B) −222 kJ. Reverse (2) and add 2 × (1): 2 × (−394) − (−566) = −788 + 566 = −222 kJ.
Q81 【CHEM-U51】 · AP Chemistry · Rate Law · Hard

For A + B → C, doubling [A] doubles the rate, but doubling [B] has no effect. The rate law is:

Answer: C) Rate = k[A]. First-order in A (rate doubles when [A] doubles), zero-order in B.
Q82 【CHEM-U71】 · AP Chemistry · Le Chatelier · Hard

For N₂(g) + 3H₂(g) ⇌ 2NH₃(g), ΔH < 0. Which change increases NH₃ yield?

Answer: C) Removing NH₃ as it forms. Removing a product shifts equilibrium to the right, increasing NH₃ yield. (A shifts left, B shifts left, D speeds both equally.)
Q83 【CHEM-U83】 · AP Chemistry · Weak Acid pH · Hard

A 0.1 M weak acid HA (Ka = 1 × 10⁻⁵) has [H⁺] approximately:

Answer: C) 10⁻³ M. For weak acids: [H⁺] = √(Ka × C) = √(10⁻⁵ × 0.1) = √10⁻⁶ = 10⁻³ M. pH ≈ 3.
Q84 【CHEM-U92】 · AP Chemistry · Nernst Equation · Hard

In the Nernst equation E = E° − (RT/nF) ln Q, what does Q represent?

Answer: B) Reaction quotient. Q is the reaction quotient (same form as K but using current concentrations); at equilibrium Q = K and E = 0.
Q85 【CHEM-U23】 · AP Chemistry · Functional Groups · Medium

Which functional group is present in ethanol (CH₃CH₂OH)?

Answer: C) Hydroxyl (alcohol). The −OH group attached to a carbon defines an alcohol.
Q86 【BIO-U11】 · AP Biology · Water Properties · Easy

Water's high specific heat is due to:

Answer: B) Hydrogen bonds between molecules. Extensive hydrogen bonding requires significant energy to break, giving water a high specific heat capacity.
Q87 【BIO-U23】 · AP Biology · Membrane Transport · Medium

Which transport mechanism requires ATP?

Answer: D) Active transport. Active transport moves substances against their concentration gradient, requiring energy (ATP).
Q88 【BIO-U31】 · AP Biology · Cellular Respiration · Hard

In eukaryotes, the Krebs cycle takes place in the:

Answer: B) Mitochondrial matrix. The Krebs (citric acid) cycle occurs in the mitochondrial matrix; the electron transport chain is on the inner membrane.
Q89 【BIO-U52】 · AP Biology · Mendelian Genetics · Medium

In a dihybrid cross (AaBb × AaBb), the expected phenotypic ratio is:

Answer: C) 9 : 3 : 3 : 1. Independent assortment in a dihybrid cross produces a 9:3:3:1 phenotypic ratio in the F2 generation.
Q90 【BIO-U61】 · AP Biology · Transcription · Hard

During transcription, the template DNA strand 3'−ATGC−5' produces which mRNA sequence?

Answer: B) 5'−UACG−3'. mRNA is synthesized 5'→3' antiparallel to the template, with U replacing T: A→U, T→A, G→C, C→G.
Q91 【BIO-U73】 · AP Biology · Fitness · Medium

In evolutionary biology, "fitness" refers to:

Answer: B) An organism's ability to survive and reproduce. Evolutionary fitness is measured by reproductive success — the passing of genes to future generations.
Q92 【BIO-U82】 · AP Biology · Energy Pyramid · Medium

In an energy pyramid, the typical efficiency of energy transfer between trophic levels is about:

Answer: B) 10%. The "10% rule" — only about 10% of energy at one trophic level is available to the next; the rest is lost as heat/metabolism.
Q93 【CHEM-U44】 · AP Chemistry · Limiting Reactant · Hard

2H₂ + O₂ → 2H₂O. If 5 mol H₂ reacts with 2 mol O₂, what is the limiting reactant and how much H₂O is produced?

Answer: B) O₂ limiting, 4 mol H₂O. Stoichiometry: 5 mol H₂ needs 2.5 mol O₂, but only 2 mol O₂ available. O₂ is limiting; 2 mol O₂ × (2 H₂O / O₂) = 4 mol H₂O.
Q94 【BIO-U12】 · AP Biology · Enzymes · Medium

The "induced fit" model of enzyme action describes:

Answer: B) The enzyme changing shape to fit the substrate. Induced fit: the enzyme's active site molds around the substrate upon binding, enhancing catalysis.
Q95 【BIO-U32】 · AP Biology · Light Reactions · Hard

The light-dependent reactions of photosynthesis occur in the:

Answer: B) Thylakoid membrane. Light reactions (including photosystems I and II, electron transport, ATP/NADPH synthesis) occur in the thylakoid membranes; the Calvin cycle is in the stroma.
Q96 【CHEM-U32】 · AP Chemistry · Ideal Gas Law · Medium

At 300 K and 2 atm, 1 mol of an ideal gas occupies what volume? (R = 0.0821 L·atm/mol·K)

Answer: B) 12.3 L. PV = nRT → V = nRT / P = (1 × 0.0821 × 300) / 2 = 24.63 / 2 = 12.3 L.
Q97 【BIO-U22】 · AP Biology · Mitosis vs Meiosis · Medium

Which is true of meiosis but NOT mitosis?

Answer: B) Reduces chromosome number by half. Meiosis produces haploid gametes through two divisions; mitosis produces identical diploid somatic cells.
Q98 【BIO-U24】 · AP Biology · Chloroplast · Medium

Which pigment absorbs primarily red and blue wavelengths for photosynthesis?

Answer: A) Chlorophyll a. Chlorophyll a absorbs red and blue light, reflecting green (which is why plants appear green); it is the primary photosynthetic pigment.
Q99 【CHEM-U45】 · AP Chemistry · Molarity · Medium

What is the molarity of 0.5 mol NaCl dissolved in 250 mL of solution?

Answer: C) 2 M. M = moles / liters = 0.5 / 0.250 = 2 M.
Q100 【BIO-U63】 · AP Biology · DNA Structure · Medium

In DNA, adenine pairs with:

Answer: C) Thymine. In DNA, A pairs with T (2 hydrogen bonds); G pairs with C (3 hydrogen bonds). In RNA, A pairs with U.

Group 6 · History, CS & Stats Extension (20 questions)

Q101 【HIST-U11】 · AP US History · Period 1 · Medium

The Columbian Exchange refers to the exchange of:

Answer: B) Plants, animals, diseases, and ideas between the Old and New Worlds. Following Columbus's voyages, this exchange transformed both hemispheres; smallpox devastated Native American populations.
Q102 【HIST-U12】 · AP US History · Period 2 · Medium

The Mayflower Compact (1620) is significant because it:

Answer: B) Established the principle of self-government. Signed by Pilgrims before landing, it created a "civil body politic" — an early example of consent of the governed.
Q103 【HIST-U15】 · AP US History · Period 5 · Medium

A direct cause of the American Civil War was:

Answer: B) The election of Abraham Lincoln in 1860. Lincoln's anti-slavery stance led Southern states to secede, beginning with South Carolina in December 1860.
Q104 【HIST-U17】 · AP US History · Period 7 · Hard

The New Deal (1933) was President Franklin Roosevelt's response to:

Answer: B) The Great Depression. The New Deal was a series of programs (Social Security, WPA, FDIC, etc.) to provide relief, recovery, and reform during the Depression.
Q105 【HIST-U18】 · AP US History · Period 8 · Hard

The Gulf of Tonkin Resolution (1964) authorized:

Answer: B) US military action in Vietnam. Following reported attacks on US ships, Congress granted President Johnson broad military powers in Vietnam, escalating US involvement.
Q106 【HIST-U21】 · AP World History · River Valley Civilizations · Easy

Which ancient civilization developed along the Indus River?

Answer: C) Harappan (Indus Valley). The Harappan or Indus Valley civilization flourished along the Indus River (modern Pakistan) around 2600–1900 BCE.
Q107 【HIST-U22】 · AP World History · Silk Road · Medium

The Silk Road was important because it:

Answer: B) Connected Europe, the Middle East, and Asia for trade and cultural exchange. The Silk Road network carried silk, spices, religions (Buddhism, Islam), and technologies between civilizations.
Q108 【MACRO-U31】 · AP Macroeconomics · Supply & Demand · Medium

If the price of a good rises, what happens to quantity demanded (law of demand)?

Answer: B) Decreases. The law of demand states that, ceteris paribus, quantity demanded decreases as price increases.
Q109 【MACRO-U32】 · AP Macroeconomics · Fiscal Policy · Hard

To combat a recession, the government should use:

Answer: B) Expansionary fiscal policy (cut taxes, increase spending). Cutting taxes and increasing government spending stimulate aggregate demand during a recession.
Q110 【MICRO-U21】 · AP Microeconomics · Elasticity · Medium

If a 10% price increase causes a 5% decrease in quantity demanded, demand is:

Answer: B) Inelastic. Price elasticity = |%ΔQ / %ΔP| = 5/10 = 0.5 < 1, so demand is inelastic (quantity is less responsive than price).
Q111 【CSA-U21】 · AP CSA · Methods · Easy

What does the keyword "void" indicate in a Java method?

Answer: B) The method returns nothing. void means the method performs an action but does not return a value.
Q112 【CSA-U22】 · AP CSA · Classes · Medium

In Java, what is a constructor?

Answer: B) A special method that initializes a new object. Constructors have the same name as the class and are called with the new keyword.
Q113 【CSA-U91】 · AP CSA · Inheritance · Hard

In Java, which keyword is used to inherit from a superclass?

Answer: C) extends. The extends keyword establishes inheritance from a class (extends for classes, implements for interfaces).
Q114 【CSA-U101】 · AP CSA · Recursion · Hard

What is the output of: public static int f(int n) { if (n <= 1) return n; return f(n − 1) + f(n − 2); } f(5)?

Answer: B) 5. The method computes the Fibonacci sequence: f(0)=0, f(1)=1, f(2)=1, f(3)=2, f(4)=3, f(5)=5.
Q115 【CSA-U102】 · AP CSA · Sorting · Medium

What is the worst-case time complexity of bubble sort?

Answer: C) O(n²). Bubble sort uses nested loops, each iterating up to n times, giving worst-case O(n²).
Q116 【CSA-U103】 · AP CSA · Searching · Easy

Binary search requires the data to be:

Answer: A) Sorted. Binary search works by repeatedly halving a sorted list; it cannot function on unsorted data.
Q117 【CSA-U12】 · AP CSP · Data · Easy

How many bits are in one byte?

Answer: B) 8. One byte equals 8 bits, allowing values from 0 to 255.
Q118 【CSA-U31】 · AP CSP · Algorithms · Medium

What is the time complexity of linear search?

Answer: C) O(n). Linear search may need to examine every element, giving O(n) time complexity.
Q119 【CSA-U32】 · AP CSP · Internet · Medium

What does HTTP stand for?

Answer: A) HyperText Transfer Protocol. HTTP is the protocol used for transmitting web pages over the internet.
Q120 【STAT-U91】 · AP Statistics · Regression · Hard

A least-squares regression line has r² = 0.81. This means:

Answer: A) 81% of the variation in y is explained by the linear relationship with x. r² (coefficient of determination) gives the fraction of variance in y explained by the model; here r = ±0.9.
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