All 50 questions from the West African Examinations Council (WAEC) Biology 2019 Objective paper, with the correct answer and a full explanation for each. Free, no signup needed.
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Which of the following structures will not be found in the nucleus of a cell?
Lysosome is not an organelle present in the nucleus; it is a separate organelle in the cytoplasm.
An example of organ level of organization is
Kidney is at the organ level of organization. Spermatozoon is at the cell level; xylem is at the tissue level; bird is at the organism level.
A structural similarity between Paramecium and Amoeba is the presence of
Paramecium has two of each of food vacuole, contractile vacuole and nucleus, while Amoeba has only one of each of these organelles; thus, the presence of two contractile vacuoles is a similarity noted here as they both possess contractile vacuoles (with Amoeba having one and Paramecium two) - the structural feature common to both is the possession of contractile vacuole(s).
The classes of plants the root systems in diagrams I and II below represent respectively are
'I' refers to a tap root while 'II' is a fibrous root. It must be noted that monocots have fibrous roots, dicots have tap roots.
What stage of cell division is illustrated in the diagram?
This is the metaphase stage of cell division.
The part labelled I is the
The part labelled 'I' is the centriole, the structure that forms the spindle.
The rate of diffusion of molecules between two media will be higher if
A high difference in concentration allows for a high diffusion rate and vice-versa.
Anaerobic respiration in the organism illustrated in the diagram below produces carbon dioxide and
The organism represented by the diagram is yeast. Anaerobic respiration in yeast produces ethanol and carbon dioxide.
Underground storage stems which grow horizontally in the soil are
Underground storage stems which grow horizontally in the soil are rhizomes.
Muscle fatigue in the body of an athlete is due to
Muscle fatigue as a result of lactic acid that accumulates during anaerobic respiration in the muscles.
The heart can beat continuously without being fatigued because it is composed of
The heart can beat continuously without being fatigued because it is composed of cardiac muscles.
The products of tissue respiration are
The products of aerobic respiration (tissue respiration) are energy, carbon dioxide and water: C6H12O6+6O2 -> 6CO2+6H2O+Energy.
Excretory products in plants responsible for the colouration of flowers are called
Anthocyanins are responsible for the various flower colours. Anthocyanins are excretory products with different colours.
The process of maintaining a steady internal environment is known as
The maintenance of a fairly constant internal environment is known as homeostasis.
Which of the following statements is not true about hormones?
Hormonal responses are not voluntary; they are involuntary/automatic responses.
[The diagram below is an illustration of a human brain] The part labelled I is the
I - cerebrum, II - Spinal Cord (as identified in the diagram).
The function of the part labelled II is that it controls
The part labelled 'II' is the spinal cord. The spinal cord is responsible for the coordination of simple reflex actions (many involuntary actions).
To focus on a distant object, the ciliary muscles of the eye
To focus on a distant object, the ciliary muscles of the eye relaxes and the eye lens gets thinner.
The main function of the amniotic fluid is for
The main function of the amniotic fluid is to protect the foetus from shock.
[The diagram below is an illustration of the longitudinal section of a flower] Which part of the flower is responsible for the protection of young flower buds?
The flower part that protects other floral parts is the sepal, labelled II.
The essential parts of the flower are labelled
The essential parts of the flower are labelled IV, V and VI.
Deficiency in insulin could lead to
Insulin is the hormone released by the pancreas for the conversion of excess glucose into glycogen. Deficiency of insulin leads to diabetes.
Which of the following forms of energy is utilized during photosynthesis?
The energy for photosynthesis comes from the sun (solar energy).
Light is excluded from a water culture experiment in order to
Light is excluded from a water culture experiment in order to prevent the growth of algae.
The major mineral present in the shell of Molluscs is
Calcium is the major mineral element present in the shell of Mollusca.
The digestion of proteins starts in the
The digestion of protein starts in the stomach. The enzyme pepsin in the gastric juice of the stomach converts protein to peptone.
Tooth decay is usually caused by
Tooth decay is usually caused by the bacteria in the mouth that metabolize sugar to acids.
The conversion of ammonium salts into nitrates is called
The conversion of ammonium salts into nitrates is called Nitrification. Nitrosomonas first converts the ammonium salts into nitrite; Nitrobacter then converts the nitrite into nitrate.
The salinity of a brackish habitat
The salinity of a brackish habitat increases during the dry season and decreases during the rainy season.
If 90 ants are found in a field with a total area of 100m^2. What is the population density of the ants?
Population Density = Total population / Total area = 90/100m^2 = 0.9 per m^2.
The complex relationship between the members of a community and their physical environment is known as
Ecology refers to the study of the inter-relationship between the living components of the ecosystem and their non-living environment.
The specific role of a species within its environment is known as its
The specific role of a species, coupled with its location in its habitat, is known as its ecological niche.
Which of the following soil fertility improvement methods will have the most negative effect on the ecosystem if not controlled?
Excessive use of fertilizer may cause unwanted algal growth.
Organisms in an ecosystem are usually grouped according to their trophic level into
Organisms are classified according to their trophic levels into producers and consumers. Consumers are further classified into primary consumers, secondary consumers and tertiary consumers.
In the pyramid of energy illustrated below, the organism with the least amount of transferred energy is
As we move from a lower trophic level to a higher trophic level, the amount of available energy decreases; thus the organism at the highest/last trophic level shown (bird) has the least amount of transferred energy.
Tall trees with branched trunks which grow above the upper storey of the forest are commonly referred to as
The trees that grow above the upper storey of the forest constitute the emergent layer.
Maize grains are best stored against insect attacks by
Maize grains are best stored against insect attacks by keeping in a silo.
Cholera is mostly spread by
The transmission of cholera is commonly through food and water. The common vector of the disease is housefly.
Which of the following resources is renewable?
Trees are renewable (as they can be re-cultivated) while coal, iron and petroleum are not.
Which of the following roles is not performed by a government agency responsible for forest maintenance?
Mining activities should be totally forbidden wherever forest conservation is intended, hence regulating mining activities is not a function performed by a government agency responsible for forest maintenance.
Which of the following factors is not a source of variation in living organisms?
Variations are as a result of genes and environment. Since genetic dissimilarity results from meiosis, meiosis can also be linked to variation. Mitosis has nothing to do with variation.
Individuals with blood group AB can donate blood to individuals with blood group(s)
AB can donate only to AB; it can however receive from A, B, AB and O. O can donate to A, B, AB and O; it can however only receive from O.
[The diagram below is an illustration of a process occurring in a living animal cell] The process occurs in the
The process (DNA replication) occurs in the nucleus.
The process is called
The process is called replication.
Which of the following nucleotides is not found in the DNA molecule?
'Uracil' is to RNA while 'thymine' is to DNA.
In a complete dominance monohybrid cross between a pure breeding yellow flowered plant Y and a pure breeding white flowered plant y, the result of the first filial generation is
Thus, all the offspring will be yellow, albeit in a heterozygous fashion.
A man whose blood group is heterozygous B is married to a woman whose blood group is also heterozygous B. Which of the following statements is correct about the blood group of their four offspring?
Thus, three out of four offspring will belong to group B while one will belong to group O.
The cross between RrTt and rrtt where R is a gene for red colour and T for tallness will result in (a) all the offspring being tall with red fruits (b) 25% tall with red fruits (c) 50% tall with red fruits (d) 75% tall with red fruits
Half of the offspring (50%) will be tall and red.
The yellow and black stripes on the body of wasps is an example of
The yellow and black stripe on the body of wasps is an example of warning colouration.
The biological importance of the dance by the worker honeybee is that it
The biological importance of the dance by the worker honey bee is that it signals the availability of food.
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