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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In a young human embryo, the excretory function is performed by the
The allantois is an embryonic membrane that performs an early excretory function, storing waste products, before the kidneys become functional.
The main respiratory substrate of all cells are
Glucose, a monosaccharide, is the main substrate broken down during cellular respiration to release energy.
A major difference between chordates and other animals is the
The defining feature of the phylum Chordata is the presence of a notochord at some stage of development.
When the forearm is raised, which muscle contracts in the process?
The biceps muscle contracts to flex the elbow and raise the forearm, while the triceps (its antagonist) relaxes.
Which of the following processes results in gamete formation?
Meiosis is the type of cell division that produces gametes (sex cells) with half the normal chromosome number.
During sexual reproduction in Spirogyra, the protoplast that moves during conjugation is referred to as the
During conjugation in Spirogyra, the protoplast of one filament (acting as the male gamete) migrates through a conjugation tube into the other filament's cell.
Tomatoes, guava and pepper belong to a group of fruits called
Tomatoes, guava and pepper are examples of berries - fleshy fruits with the entire pericarp fleshy and seeds embedded within.
Which of the following chemicals is a plant growth substance?
Indoleacetic acid (IAA) is a naturally occurring auxin, a plant growth hormone.
Human beings have relatively poorer vision at night than nocturnal animals because the human eyes
Rod cells are responsible for vision in dim light; human eyes contain comparatively fewer rods than nocturnal animals, giving humans poorer night vision.
Overproduction of somatotropic hormones in the human being could result in
Excess growth hormone (somatotropin), especially before bone growth plates fuse, causes excessive growth (gigantism).
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?
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.
Wind is an important ecological factor because it
Wind drives the movement of clouds across regions, influencing where and how much rainfall occurs.
In a bare rock environment, which of these plants is likely to be the pioneer species?
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.
Sokoto state is located in the
Sokoto State, in Nigeria's far north-west, lies within the Sahel savanna vegetation belt.
The enrichment of water bodies with inorganic nutrients such as phosphates and nitrates that can favour excessive algal growth is called
Eutrophication is the process by which excess nutrients (like phosphates and nitrates) in water bodies lead to excessive algal growth.
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?
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.
The process occurring in III is
The remaining labelled arrow in the carbon cycle, returning carbon to the atmosphere as CO2, represents respiration (of plants/animals/decomposers).
The eggs of Schistosoma sp would hatch after passing out with the faeces or urine of the patient into a larva called
Schistosoma eggs hatch in water to release a free-swimming larval stage called a miracidium, which then infects a snail intermediate host.
The body defence mechanism is characterized by
The immune response is characterized by antigens (foreign substances) triggering the body to produce specific antibodies against them.
Which of the following may result in air pollution?
Incomplete combustion of fuel releases pollutants such as carbon monoxide and soot into the air, contributing to air pollution.
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