JAMB Biology Previous Year Questions: 2020 | Biology for JAMB PDF Download

Q1: The hormone which regulates the amount of glucose in the blood us called?
(a) Adrenalin
(b) Auxin
(c) Insulin
(d) Thyroxine
Ans: (c)
Insulin is a hormone that lowers the level of glucose (a type of sugar) in the blood. It's made by the beta cells of the pancreas and released into the blood when the glucose level goes up, such as after eating. Insulin helps glucose enter the body's cells, where it can be used for energy or stored for future use.

Q2: Deamination occurs in the?
(a) Kidney
(b) Pancreas
(c) Spleen
(d) Liver
Ans: (d)
Deamination is the removal of an amino group from a molecule. Enzymes that catalyse this reaction are called deaminases. ... In situations of excess protein intake, deamination is used to break down amino acids for energy. The amino group is removed from the amino acid and converted to ammonia.

Q3: In an agricultural ecosystem, the biotic component consist of
(a) crops, pests and beneficial insects
(b) crops, temperature and humidity
(c) pests, beneficial insects and water
(d) crops, water and soil
Ans: (a)
Biotic components, or biotic factors, can be described as any living component that affects another organism or shapes the ecosystem. This includes both animals that consume other organisms within their ecosystem, and the organism that is being consumed.

Q4: Epiphytes growing on the branches of trees provide an example of the relationship known as?
(a) parasitism
(b) commensalism
(c) saprophytism
(d) holophytism
Ans: (b)
Commensalism is a long-term biological interaction in which members of one species gain benefits while those of the other species neither benefit nor are harmed.

Q5: The hypha of rhizopus is said to be non-septate because it
(a) does not contain chloropyll
(b) has no cross wall
(c) is vacuoled
(d) stores oil globus
Ans: (b)
Hyphae can form a tangled network called a mycelium and form the thallus (body) of fleshy fungi. Hyphae that have walls between the cells are called septate hyphae; hyphae that lack walls and cell membranes between the cells are called nonseptate or coenocytic hyphae)

Q6: The function of ribosome in cells is
(a) protein synthesis
(b) starch synthesis
(c) transport of material
(d) lipid storage
Ans: (a)
The ribosome, a cell organelle, functions as a micro-machine for making proteins.

Q7: In which of the following does external fertilization take place?
(a) toad
(b) lizard
(c) bird
(d) cockroach
Ans: (a)
External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body. It is contrasted with internal fertilization, in which sperm are introduced via insemination and then combine with an egg inside the body of a female organism.

Q8:The villus in the small intestine is significant because
(a) Increases the surface area for absorption
(b) increases the surface area for digestion
(c) assists in mixing digested food
(d) assists in filtering undigested food
Ans: (a)
Villus, plural villi, in anatomy any of the small, slender, vascular projections that increase the surface area of a membrane. The villi of the small intestine project into the intestinal cavity, greatly increasing the surface area for food absorption and adding digestive secretions.

Q9: The butterfly is of great economic importance because
(a) of it's use in scientific studies
(b) it sucks nectar from flowers
(c) it adds to the beauty of the environment
(d) it pollinates flowers of crops and other plants
Ans: (d)
Butterflies play important roles as pollinators to most agricultural crops.

Q10: The bright colours of the comb and feathers in the peacock are for?
(a) sex differentiation
(b) beauty
(c) courtship
(d) defence
Ans: (c)
The male peacocks display their beautiful fanned trains as part of their courtship behaviour.

Q11: What is the term used to describe biotic and abiotic factors in the environment of the organism?
(a) habitat
(b) biome
(c) ecosystem
(d) ecological niche
Ans: (c)
An ecosystem consists of all the biotic and abiotic factors that influence that community.
Examples of abiotic factors are water, air, soil, sunlight, and minerals. Biotic factors are living or once-living organisms in the ecosystem. These are obtained from the biosphere and are capable of reproduction. Examples of biotic factors are animals, birds, plants, fungi, and other similar organisms.

Q12: Which of the following instruments is NOT used in measuring abiotic factors in any habitat?
(a) microscope
(b) windvane
(c) thermometer
(d) hygrometer
Ans: (a)
In biology and ecology, abiotic components or abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Abiotic factors and the phenomena associated with them underpin biology as a whole.

Q13: The smallest living organisms which share the characteristics of both living and non-living matter are
(a) bacteria
(b) fungi
(c) viruses
(d) protozoa
Ans: (c)
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all types of life forms, from animals and plants to microorganisms, including bacteria and archaea.

Q14: The process by which a red blood cell placed in distilled water absorbs water until it burst and realease it's content into the surrounding is known as
(a) osmosis
(b) plasmolysis
(c) turgidity
(d) hemolysis
Ans: (d)
The body normally destroys old or faulty red blood cells in the spleen or other parts of your body through a process called hemolysis
Hemolysis is the destruction of red blood cells which leads to the release of haemoglobin from within the red blood cells into the blood plasma.

Q15: Which of the following waste products in plants is excreted through the stomata and lenticles?
(a) carbon dioxide
(b) alkaloids
(c) tannins
(d) anthoocyanins
Ans: (a)
The waste products of a plant are water vapour, carbon dioxide and oxygen.

Q16: Use the diagram to answer the question
The vertebra illustrated is
(a) lumber
(b) thoracic
(c) caudal
(d) cervical
Ans: (b)
The thoracic spine is the second segment of the vertebral column, located between the cervical and lumbar vertebral segments. It consists of twelve vertebrae, which are separated by intervertebral discs. Along with the sternum and ribs, the thoracic spine forms part of the thoracic cage.

Q17: Use the diagram to answer the question
The neural arch is labelled 
(a) i
(b) ii
(c) iii
(d) iv
Ans: (b)

Q18: The excretory structure in the earthworm is the
(a) malphighian tubule
(b) flame cell
(c) nephridium
(d) kidney
Ans: (c) 
Nephridia dispose metabolic wastes from an animal's body. There are two categories of Nephridia, namely metanephridia and protonephridia.

Q19: In which of the following vertebrates does the skin function as a respiratory surface
(a) rat
(b) lizard
(c) fish
(d) frog
Ans: (d)
At the early stages of their life, amphibians utilize gills for breathing. As they mature, they develop primitive lungs; additionally, they are able to breathe through their skin.

Q20:The process of walking is under the control of the part of the brain called
(a) optic lobe
(b) olfactory lobe
(c) cerebellum
(d) medulla oblongata
Ans: (d)
The cerebellum is a part of the brain that plays a vital role in virtually all physical movement. This part of the brain helps a person drive, throw a ball, or walk across the room. The cerebellum also assists people with eye movement and vision.

Q21: The ability of the eyes to focus on both near and distance objects is termed
(a) image formation
(b) refraction
(c) hypermetropia
(d) accommodation
Ans: (d)
Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies.
When our eyes see distant objects then the ciliary muscles relax and the focal length is maximum in this position.

Q22: A group pf organism of different species living in a particular area is described as a
(a) colony
(b) community
(c) population
(d) niche
Ans: (b)
Community, also called biological community, in biology, an interacting group of various species in a common location

Q23: The biological association that contributes directly to succession in a community is
(a) competition
(b) predation
(c) parasitism
(d) commensalism
Ans: (a)
Competition is an interaction between organisms or species in which both the organisms or species are harmed.

Q24: Floating microscopic heterotrophs are mostly grouped as
(a) phytoplankton
(b) zooplankton
(c) microbes
(d) nekton
Ans: (a)
Phytoplanktons are microscopic marine organisms at the bottom of the food chain. Most phytoplanktons are buoyant and float in the upper part of the ocean.
Phytoplanktons are the autotrophic components of the plankton community and a key part of ocean and freshwater ecosystems.

Q25: Vaccination is carried out in order to
(a) check the production of poison
(b) increase the activities of white blood cells
(c) increase the number of red blood cells
(d) stimulate the production of anti-bodies
Ans: (d)
Vaccination is carried out to stimulate the production of antibodies. When a person is vaccinated, a weakened or inactivated form of a pathogen or its components is introduced into their body. This triggers the immune system to recognize the pathogen as foreign and mount an immune response. The immune system produces specific proteins called antibodies that are capable of recognizing and neutralizing the pathogen. These antibodies remain in the body, providing immunity against future infections by the same pathogen.

Q26: For growth to occur in organisms, the rate of
(a) anabolism must exceed that of catabolism
(b) catabolism must exceed that of anabolism
(c) food storage must be low
(d) food storage must be high
Ans: (a)
Anabolism is the set of metabolic pathways that construct molecules from smaller units. These reactions require energy, known also as an endergonic process. Anabolism is the building-up aspect of metabolism, whereas catabolism is the breaking-down aspect.

Q27: The probability of a baby being a boy or a girl depends on the contribution of the
(a) father's sex cells
(b) father's stomatic chromosome
(c) mother's sex cell
(d) mother's X-chromosome
Ans: (a)
A man with many brothers is more likely to have sons, while a man with many sisters is more likely to have daughters.

Q28: Both recesssive and dominant characters are found
(a) on different chromosome in the cell
(b) at the same logus of a homologous chromosome
(c) at a different loci of a homologous chromosome
(d) on the same chromatid in a chromosome
Ans: (b)
In genetics, genes are segments of DNA located on chromosomes, and they determine the inheritance of specific traits or characteristics. Alleles are different versions of a gene that can produce variations in a trait.
In a diploid organism, such as humans, we have two copies of each chromosome, one inherited from each parent. These two copies of a gene are called alleles. They are found at the same locus (specific position) on homologous chromosomes.
Dominant alleles are expressed phenotypically even if there is only one copy of the allele, while recessive alleles are expressed phenotypically only when there are two copies of the allele (homozygous recessive).
Therefore, option (b) is the correct answer as it states that both recessive and dominant characters are found at the same locus of a homologous chromosome.

Q29: In a popu;ation of living things, the parameters of size, height, weight and colours are examoles of
(a) continuous variation
(b) non-heritable variation
(c) discontinuous variation
(d) physiological variation
Ans: (a)
Continuous variation is the combined effect of many genes (known as polygenic inheritance) and is often significantly affected by environmental influences.

Q30: Use the diagram to answer the question.
The process of water loss and intake indicated by the arrows labelled i and ii are respectively
(a) evaporation and osmosis
(b) exhalation and osmosis
(c) osmosis and diffusion
(d) urination and diffusion
Ans: (b)
Exhalation refers to the process of expelling air from the lungs, and during exhalation, some water vapor is also lost from the respiratory system. This accounts for water loss.
Osmosis, on the other hand, is the movement of water molecules across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration. Osmosis is responsible for the intake or absorption of water in various biological processes.

Q31: The noticeable adaptation of the animal to it's aquatic habitat is the possession of
(a) webbed digits
(b) four limb
(c) wide mouth
(d) large eyes
Ans: (a)
Webbed digits, or the presence of webbing between the digits (fingers or toes), is a notable adaptation in animals living in aquatic habitats. This adaptation helps them to be more efficient swimmers by providing increased surface area, which enhances their ability to propel through water.
Animals with webbed digits, such as ducks, swans, otters, and frogs, have evolved this characteristic to aid in swimming, diving, and maneuvering in water. The webbing between their digits acts as a paddle, allowing them to generate more force and propel themselves through the water with greater ease.

Q32: Paternity disputes can most accurately be resolved through the use of
(a) blood group typing
(b) finger printing
(c) tongue rolling
(d) DNA Analysis
Ans: (d)
Paternity disputes, which involve determining the biological father of a child, can be most accurately resolved through the use of DNA analysis. DNA (deoxyribonucleic acid) is a molecule that carries the genetic information of an individual, and each person's DNA is unique, except in the case of identical twins.
DNA analysis involves comparing the DNA profiles of the child, the alleged father, and the mother (if available). By examining specific regions of DNA that are known to vary between individuals (such as short tandem repeats or single nucleotide polymorphisms), scientists can determine whether the alleged father shares genetic markers with the child.
The results of DNA analysis provide highly accurate and conclusive evidence of paternity. The probability of paternity can be calculated based on the matching DNA profiles, providing a scientifically reliable method to resolve paternity disputes.

Q33: Use the table below to answer the question.
High relative humidity will be expected in Zones
(a) ii and iv
(b) ii and iii
(c) i and iii
(d) i and iv
Ans: (b)
Relative humidity refers to the amount of moisture present in the air compared to the maximum amount of moisture the air can hold at a specific temperature. It is influenced by factors such as temperature, air pressure, and the presence of water sources.
Zone ii and iii are the ones where high relative humidity would be expected. The reason for this is that both zones are mentioned in the answer option, indicating that they both have conditions suitable for high relative humidity.
Without further information or context, it is difficult to determine the exact characteristics or locations of these zones. However, based on the given options, the answer would be (b) ii and iii.

Q34: Use the table to answer the question.
 Which of the zones is likely to be a desert?
(a) i
(b) ii
(c) iii
(d) iv
Ans: (a)

Q35: When bacteria swim from cold to warm regions, this is known as
(a) positive phototaxis
(b) negative phototaxis
(c) positive thermotaxis
(d) negative chemotaxis
Ans: (c)
The movement of organisms in relation to heat: movement toward a higher temperature is positive thermotaxis and that toward a lower temperature negative thermotaxis.

Q36: The only caste in the termite colony whose members can feed themselves are the
(a) workers
(b) reproductives
(c) soldiers
(d) nymphs
Ans: (a)
In a termite colony, the workers are the caste responsible for gathering food and feeding the other members of the colony, including the reproductives, soldiers, and nymphs. Workers are specialized in tasks such as foraging for food, constructing and maintaining the nest, and caring for the young. They are the most numerous caste in a termite colony and play a crucial role in the survival and functioning of the colony.

Q37: Which of the following os the best explanation for a child who is phenotypically short and born of two tall parents
(a) both parent possess genes for shortness
(b) the father possess a gene for shortness
(c) nature makes the child short
(d) None of the above
Ans: (a)
When a child is phenotypically short (meaning they appear short) despite having two tall parents, it suggests that both parents carry genes for shortness. In genetics, height is influenced by multiple genes, with contributions from both parents. Even if the parents themselves are tall, they can still carry and pass on genes for short stature.
Height is a polygenic trait, which means it is influenced by the interaction of multiple genes. Each parent contributes a set of genes to their child, and the combination of these genes determines the child's height potential. It is possible for parents who are tall to carry and pass on genes for shortness if they have inherited those genes from their own parents or ancestors.
Therefore, when a child is born short despite having tall parents, it is likely that both parents possess genes for shortness, which were inherited by the child and expressed phenotypically.

Q38: Which of the following vertebrates has the most simple structured heart
(a) reptile
(b) fish
(c) mammal
(d) Amphibian
Ans: (b)
Among the given options, fish have the most simple structured heart. Fish have a two-chambered heart, consisting of a single atrium and a single ventricle. This means that blood flows through the heart in a relatively simple pathway: it enters the atrium, passes through the ventricle, and is pumped out to the gills for oxygenation.
In contrast, the other vertebrates listed in the options have more complex heart structures. Reptiles and amphibians generally have a three-chambered heart, with two atria and a single ventricle. Mammals, including humans, have a four-chambered heart, with two atria and two ventricles. The presence of additional chambers allows for a more efficient separation of oxygenated and deoxygenated blood and enables a higher level of systemic circulation.
Therefore, among the given options, fish have the most simple structured heart with only two chambers.

Q39: Use the diagram to answer the question.
The type of protective adaption exhibited by the animal is
(a) disruptive colouration
(b) flash colouration
(c) countershading colouration
(d) warning colouration
Ans: (c)
Countershading is a form of concealing colouration in which the upper surfaces of the body are more darkly pigmented than the unilluminated lower areas, giving the body a more uniform darkness and a lack of depth relief.
In disruptive coloration, the identity and location of an animal may be concealed through a coloration pattern that causes visual disruption because the pattern does not coincide with the shape and outline of the animal's body.

Q40: Use the diagram to answer the question.
The structure labelled i is
(a) photosensitive
(b) radiosensitive
(c) chemoreceptive
(d) tactile
Ans: (d)
The structure labeled "i" is described as tactile. Tactile refers to the sense of touch or the ability to perceive physical contact or pressure. Tactile receptors are responsible for detecting touch, pressure, vibration, and other tactile sensations.
Photosensitive refers to being sensitive to light, typically related to the ability to detect and respond to light stimuli. Radiosensitive refers to sensitivity to radiation. Chemoreceptive refers to the ability to detect and respond to chemical stimuli.
Since the structure in question is labeled "i," which implies a physical structure rather than a sensory ability related to light, radiation, or chemicals, the most appropriate answer is (d) tactile.