POST UTME UNIBEN 2025 Biology | Objective

Are you preparing for POST UTME UNIBEN exams? Reviewing past questions is one of the most effective ways to guarantee a high score. This practice hub features authentic 2025 Biology (Objective) questions designed to simulate the real exam environment.

Practice these randomly selected questions to test your readiness.

Question 1
In a tropical rainforest e\cosystem, what is the primary role of the leaf's cuticle in relation to transpiration?
Correct A. To reduce water loss through transpiration
B. To increase water uptake through root absorption
C. To facilitate gas exchange between the leaf and the atmosphere
D. To protect the leaf from excessive sunlight

Correct Answer: A

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Question 2
A 2.5 L flask contains 0.5 M HCl. If 25 mL of 1.5 M NaOH is added to the flask, what is the resulting concentration of the solution?
A. 0.55 M
Correct B. 0.65 M
C. 0.75 M
D. 0.85 M

Correct Answer: B

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Question 3
A plant hormone that promotes cell elongation is
Correct A. Auxin
B. Cytokinin
C. Ethylene
D. Abscisic acid

Correct Answer: A

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Question 4
The process by which plants convert light energy into chemical energy is
A. Respiration
Correct B. Photosynthesis
C. Transpiration
D. Translocation

Correct Answer: B

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Question 5
The diagram below shows a cross-section of a plant root. Identify the structure labeled A
Correct A. Root hair cell
B. Xylem vessel
C. Phloem sieve cell
D. Cortex cell

Correct Answer: A

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Question 6
In the context of osmoregulation, what is the primary function of the kidneys in a desert-dwelling organism?
A. To conserve water by reabsorbing water from the filtrate
B. To excrete excess salt by producing a highly concentrated urine
C. To regulate electrolyte balance by reabsorbing or excreting ions
Correct D. To produce a highly concentrated urine by reabsorbing water from the filtrate

Correct Answer: D

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Question 7
A cell is placed in a solution with a pH of 5.5. What will happen to the cell membrane?
A. The cell membrane will become more permeable to hydrogen ions
Correct B. The cell membrane will become less permeable to hydrogen ions
C. The cell membrane will remain unchanged
D. The cell membrane will undergo lysis

Correct Answer: B

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Question 8
A diagram of a plant cell is shown below. What is the function of the structure labeled 'X'?
Correct A. To store water and nutrients
B. To synthesize proteins
C. To store genetic material
D. To regulate cell growth

Correct Answer: A

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Question 9
A diagram of a human kidney is shown below. What is the function of the structure labeled 'Y'?
Correct A. To filter waste products from the blood
B. To regulate electrolyte balance
C. To produce a highly concentrated urine
D. To store water and nutrients

Correct Answer: A

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Question 10
A diagram of a human digestive system is shown below. What is the function of the structure labeled 'Z'?
A. To break down proteins into amino acids
Correct B. To absorb nutrients into the bloodstream
C. To store water and nutrients
D. To regulate electrolyte balance

Correct Answer: B

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Question 11
In a population of Drosophila melanogaster, the frequency of the recessive allele 'a' is 0.2. If the population is in Hardy-Weinberg equilibrium, what is the frequency of the homozygous dominant genotype 'AA'?
A. 0.36
Correct B. 0.64
C. 0.72
D. 0.84

Correct Answer: B

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Question 12
A cell in the G2 phase of the cell cycle has a DNA content of 8C. If the cell proceeds to mitosis, what will be the DNA content of the daughter cells?
A. 2C
Correct B. 4C
C. 8C
D. 16C

Correct Answer: B

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Question 13
A plant with the genotype 'Rr' is crossed with a plant with the genotype 'RR'. What is the probability that the offspring will have the genotype 'rr'?
A. 0.25
Correct B. 0.5
C. 0.75
D. 0.9

Correct Answer: B

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Question 14
A diagram shows a plant with 5 petals. If the plant is a homozygous dominant for the gene controlling petal number, what is the probability that the offspring will have 5 petals?
A. 0.5
Correct B. 1
C. 0.75
D. 0.9

Correct Answer: B

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Question 15
A diagram shows a plant with 5 petals. If the plant is a heterozygous for the gene controlling petal number, what is the probability that the offspring will have 5 petals?
A. 0.25
Correct B. 0.5
C. 0.75
D. 0.9

Correct Answer: B

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Question 16
In a population of Drosophila melanogaster, the frequency of the recessive allele 'b' is 0.2. If the population is in Hardy-Weinberg equilibrium, what is the frequency of the homozygous dominant genotype 'BB'?
Correct A. 0.64
B. 0.8
C. 0.2
D. 0.4

Correct Answer: A

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Question 17
A plant with the genotype 'Tt' is crossed with a plant with the genotype 'tt'. What is the probability that the offspring will have the genotype 'TT'?
Correct A. 1/4
B. 1/2
C. 3/4
D. 2/3

Correct Answer: A

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Question 18
A neuron has a resting membrane potential of -70 mV. If the neuron is depolarized by 20 mV, what is the new membrane potential?
Correct A. -50
B. -70
C. -60
D. -80

Correct Answer: A

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Question 19
A diagram of the human eye is shown below. What is the function of the part labeled 'A'?
A. to focus light
Correct B. to detect light
C. to re\fract light
D. to absorb light

Correct Answer: B

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Question 20
A diagram of the human brain is shown below. What is the function of the part labeled 'B'?
A. to control movement
B. to regulate body temperature
Correct C. to process sensory information
D. to store memories

Correct Answer: C

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Question 21
The enzyme catalase breaks down hydrogen peroxide into water and oxygen. If 10 mL of 3% hydrogen peroxide is treated with 1 g of catalase, what is the volume of oxygen gas produced at STP?
A. 1.5 mL
Correct B. 2.8 mL
C. 4.2 mL
D. 5.6 mL

Correct Answer: B

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Question 22
A population of bacteria grows according to the \logistic growth equation: dP/dt = rP\( 1 - P/K \). If the initial population is 100 and the carrying capacity is 1000, what is the population size after 10 generations?
A. 500
B. 750
C. 900
Correct D. 950

Correct Answer: D

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Question 23
A cell membrane is composed of a phospholipid bilayer with embedded proteins. Which of the following is a characteristic of the phospholipid bilayer?
A. It is impermeable to water
B. It is impermeable to ions
Correct C. It is selectively permeable
D. It is impermeable to glu\cose

Correct Answer: C

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Question 24
A person with a genetic disorder has a mutation in the gene that codes for a protein. Which of the following is a possible consequence of this mutation?
A. The protein is produced in excess
B. The protein is produced in deficiency
Correct C. The protein is produced with a change in function
D. The protein is not produced at all

Correct Answer: C

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Question 25
A plant has a photosynthetic rate of 10 μmol CO2/s. If the light intensity is increased by a factor of 2, what is the new photosynthetic rate?
A. 5 μmol CO2/s
B. 10 μmol CO2/s
C. 15 μmol CO2/s
Correct D. 20 μmol CO2/s

Correct Answer: D

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