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Post-UTME Biology 2018 Objective Past Questions

All 20 questions from the Post-UTME Screening (Post-UTME) Biology 2018 Objective paper, with the correct answer and a full explanation for each. Free, no signup needed.

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Biology 2018 Objective — Question 1

Adrenaline, the flight hormone, is produced by the

  • A. thyroid gland
  • B. pancreas
  • C. adrenal glandCorrect
  • D. liver

Explanation

Adrenaline (the 'fight or flight' hormone) is produced by the adrenal glands.

Biology 2018 Objective — Question 2

A secchi disc is an opaque, typically white disc used to gauge

  • A. rainfall
  • B. tides
  • C. waves
  • D. the transparency of waterCorrect

Explanation

A secchi disc is lowered into water to measure its transparency/turbidity.

Biology 2018 Objective — Question 3

During excretion of urea, there is also a corresponding reabsorption of water into the blood. This reabsorption takes place in the

  • A. uriniferous tubulesCorrect
  • B. Bowman's capsule
  • C. glomerulus
  • D. Malpighian capsule

Explanation

Reabsorption of water and useful substances occurs along the uriniferous (renal) tubules.

Biology 2018 Objective — Question 4

Crabs live in water and thus possess

  • A. scaly legs
  • B. light bones
  • C. two walking legs
  • D. gillsCorrect

Explanation

Crabs are aquatic crustaceans that respire using gills, and become more turgid in water due to osmotic uptake.

Biology 2018 Objective — Question 5

Haptotropism is the movement of a plant (especially tendrils) in response to

  • A. light
  • B. gravity
  • C. touch stimulusCorrect
  • D. water

Explanation

Haptotropism (thigmotropism) is the growth response of a plant part, such as a tendril, to touch.

Biology 2018 Objective — Question 6

Which vertebra has a projection called the odontoid process?

  • A. atlas
  • B. axisCorrect
  • C. thoracic
  • D. lumbar

Explanation

The axis (2nd cervical vertebra) has the odontoid process (dens), around which the atlas rotates.

Biology 2018 Objective — Question 7

Energy is produced during anaerobic respiration of

  • A. glucose only via Krebs cycle
  • B. glucose with full oxidation
  • C. glucose without oxygenCorrect
  • D. proteins only

Explanation

Anaerobic respiration of glucose (without oxygen) still yields a small amount of usable energy via glycolysis/fermentation.

Biology 2018 Objective — Question 8

Cold-blooded organisms can also be said to be

  • A. homeothermic
  • B. endothermic
  • C. poikilothermicCorrect
  • D. warm-blooded

Explanation

Cold-blooded (variable body temperature) organisms are described as poikilothermic.

Biology 2018 Objective — Question 9

Underground stems which grow horizontally through the soil are

  • A. bulbs
  • B. rhizomesCorrect
  • C. runners
  • D. corms

Explanation

Rhizomes are horizontal underground stems that grow laterally through the soil.

Biology 2018 Objective — Question 10

Which of the following should be killed in order to destroy a termite colony?

  • A. The king
  • B. The queenCorrect
  • C. The workers
  • D. The soldiers

Explanation

The queen is the primary reproductive individual of the colony; destroying her collapses the colony's ability to reproduce and sustain itself.

Biology 2018 Objective — Question 11

Use the diagram above (a food web: Green plants -> Grasshopper (G) -> Lizards (H) -> Hawk (I); Snakes (J) -> Owl (K), with lizards also preyed on by snakes) to answer this question. From the diagram, which of the following is most likely to result in an increase in the population of H?

  • A. An increase in the population of I
  • B. A decrease in the population of K
  • C. A decrease in the population of JCorrect
  • D. A decrease in the population of G

Explanation

Lizards (H) are preyed upon by snakes (J) as well as hawks; a decrease in the snake population (J) would reduce predation pressure on lizards, allowing H to increase.

Biology 2018 Objective — Question 12

Wind is an important ecological factor because it

  • A. clears water bodies of suspended particles
  • B. increases the salinity of water bodies
  • C. affects the depth of water to which light can penetrate
  • D. controls cloud movement and hence the distribution of rainfallCorrect

Explanation

Wind drives the movement of clouds across regions, influencing where and how much rainfall occurs.

Biology 2018 Objective — Question 13

In a bare rock environment, which of these plants is likely to be the pioneer species?

  • A. LichensCorrect
  • B. Ferns
  • C. Spermatophytes
  • D. Bryophytes

Explanation

Lichens are classic pioneer organisms on bare rock, as they can survive with minimal soil and gradually break down rock to help form soil for later colonisers.

Biology 2018 Objective — Question 14

Sokoto state is located in the

  • A. tropical rain forest
  • B. southern guinea savanna
  • C. Sahel savannaCorrect
  • D. desert

Explanation

Sokoto State, in Nigeria's far north-west, lies within the Sahel savanna vegetation belt.

Biology 2018 Objective — Question 15

The enrichment of water bodies with inorganic nutrients such as phosphates and nitrates that can favour excessive algal growth is called

  • A. nitrification
  • B. ammonification
  • C. eutrophicationCorrect
  • D. denitrification

Explanation

Eutrophication is the process by which excess nutrients (like phosphates and nitrates) in water bodies lead to excessive algal growth.

Biology 2018 Objective — Question 16

Use the diagram below (a carbon cycle showing CO2 in the atmosphere, Animals, Coal and Green plants, connected by labelled processes I, II and III) to answer this question and the next. In the diagram, what processes occur in I and II respectively?

  • A. Combustion and precipitation
  • B. Photosynthesis and respirationCorrect
  • C. Precipitation and photosynthesis
  • D. Respiration and photosynthesis

Explanation

In a carbon cycle diagram, green plants remove CO2 from the atmosphere via photosynthesis, while animals (and plants) return CO2 to the atmosphere via respiration.

Biology 2018 Objective — Question 17

The process occurring in III is

  • A. combustion
  • B. reduction
  • C. precipitation
  • D. respirationCorrect

Explanation

The remaining labelled arrow in the carbon cycle, returning carbon to the atmosphere as CO2, represents respiration (of plants/animals/decomposers).

Biology 2018 Objective — Question 18

The eggs of Schistosoma sp would hatch after passing out with the faeces or urine of the patient into a larva called

  • A. miracidiumCorrect
  • B. cercaria
  • C. caterpillar
  • D. cysticercus

Explanation

Schistosoma eggs hatch in water to release a free-swimming larval stage called a miracidium, which then infects a snail intermediate host.

Biology 2018 Objective — Question 19

The body defence mechanism is characterized by

  • A. antibodies stimulating the production of antigens
  • B. toxins acting as antibodies
  • C. any antibody counteracting the action of any toxin
  • D. antigens stimulating the production of antibodiesCorrect

Explanation

The immune response is characterized by antigens (foreign substances) triggering the body to produce specific antibodies against them.

Biology 2018 Objective — Question 20

Which of the following may result in air pollution?

  • A. Incomplete combustion of fuelCorrect
  • B. Old vehicles
  • C. Sewage
  • D. Noise

Explanation

Incomplete combustion of fuel releases pollutants such as carbon monoxide and soot into the air, contributing to air pollution.

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