Quiz 2 of 20

Free WAEC Biology Theory Past Questions


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2021 WAEC Biology Theory Question 1

A sample of human blood was put in a test tube and allowed to spin in a centrifuge. The components of the blood sample were clearly separated.

(a) List the four main components of blood that would be in the test tube.


Components of Blood

  • Blood plasma
  • Platelets (thrombocytes)
  • White blood cells (leucocytes)
  • Red blood cells (erythrocytes)


(b) Name the components of the blood that:

(i) Would form the top layer in the test tube

Answer: Blood Plasma

(ii) Destroys pathogens

Answer: White blood cells/leucocytes

(iii) Is bi-concave in shape

Answer:  Red blood cells/erythrocytes

(iv) Would be relatively low in a haemophilic condition

Answer:  Platelets (thrombocytes)

(v) Is produced in the bone marrow


– Platelets (thrombocytes)
– White blood cells/leucocytes
– Red blood cells/erythrocytes

(vi) Is a thrombocyte

Answer: Platelets

(vii) Is nucleated

Answer: White blood cells/leucocytes


(c) Mention three chemical substances transported by the blood component named in 1(b)(i)

Answer:  Chemical substances transported by the blood component named in 1(b)(i) blood plasma:

  • Hormones e.g. Thyroxine, adrenaline, insulin, progesterone.
  • Digested food substances e.g. glucose, amino acid.
  • Antibodies/antigens
  • Dissolved gases e.g. oxygen, carbon (iv) oxide
  • Toxins
  • Mineral salts e.g. Magnesium, copper, potassium and zinc.
  • Urea, uric acid
  • Water
  • Vitamins


(d) List four diseases associated with blood.

Answer: Diseases Associated with the Blood

Anaemia, Hepatitis, Sickle cell anaemia Haemophilia, AIDS, Malaria, Leukaemia.


(e) Explain briefly why a disease of the blood could be dangerous.

Answer: Reason a disease of the blood is deadly

The blood circulates throughout the body i.e. it is a medium of transportation within the body. As it circulates, it makes contact with major organs of the body, which makes it easy for a disease to be deadly.

Also, blood disease could attack any component of blood and threaten life.

2022 WAEC Biology Theory Question 5

a. (i) State three differences between the alimentary canals of earthworm and cockroach.


s/n Earthworm Cockroach
1. It lacks crop It has crop
2. It lacks colon It has colon
3. The digestive track
is straight and simple
The digestive track is
curved and more
4. They lack dental pads They possess dental pads.

(ii) State three similarities between the alimentary canals of earthworm and cockroach.


– They  both have pharynx
– They both have gizzard
– They both have oesophagus


b. The diagram below is an illustration of a biological cycle.

Study it and answer questions 5(b)i) to 5(b)(iii)


(i) Name the biological cycle

Answer: Water cycle

(ii) Explain briefly three roles played by plants and animals in the cycle.


– Plants absorb water from the soil. The water moves from the roots through the stems to the leaves. Once water reaches the leaves, some of it evaporates from the leaves, adding to the amount of water vapor in the air. This process of evaporation through plant leaves is called transpiration.

– Water cycle is a product of respiration in plants. Water is carried from the roots of the plant throughout the plant to the underside of the leaves where it evaporates off into the atmosphere.

– Animals release water vapor into the water cycle when they exhale

– Animals contribute to the water cycle mainly through breathing, perspiration, and excretion of waste.

(iii) Name the processes that occur in X, Y and Z.


– X represents condensation
– Y represents transpiration/respiration
– Z represents evaporation


c. Complete the table below.


Organ associated with
excretion in humans
Three diseases each that
affect the organ
1. Lungs Lung cancer, pneumonia
2. Kidney Kidney stones, oedema,
kidney cysts, nephritis


d. (i) What is decay of organic matter?


Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts.

(ii) Name two groups of organisms that cause decay of organic matter.


Most decomposers are microscopic organisms, including protozoa and bacteria.

Other decomposers are big enough to see without a microscope. They include fungi along with invertebrate organisms sometimes called detritivores, which include earthworms, termites, and millipedes.

(iii) State one other factor that causes decay.


– Temperature
– Oxygen (aeration)

(iv) Name the biological cycle that involves decay.

Answer: Nitrogen cycle

e. Explain briefly the mode of nutrition in carnivorous plants.


These are plants that obtain energy by feeding on small insects. They have developed special structures to trap their prey. Examples of insectivorous plants are pitcher plants, venus flytraps, and sundew.

In the pitcher plant, some of its leaves are modified to form a pitcher, like a container; a deep cavity filled with digestive liquid. The inner walls of the containers are slippery and smooth. Once insects are trapped, they are unable to come out.

At the bottom, they are digested by a pool of liquid containing digestive enzymes.

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