2018 - WAEC Biology Past Questions and Answers - page 2

11

Which of the following structures would carry out cellular respiration? A

A
germinating seed
B
decolorised leaf
C
dry leaf
D
boiled cowpea
correct option: a

Germinating seeds respire by using oxygen and producing carbon dioxide gas, they respire in the similar way as animals.

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12

Which of the following is NOT an excretory product of animals?

A
carbondioxide
B
urea
C
sweat
D
oxygen
correct option: d

Animals take in oxygen in respiratory process, taking out carbondioxide. 

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13

An example of homeostasis in living organisms is

A
cooling effect resulting from evaporation of water from the body surface
B
root hairs of a plant growing towards the source of light
C
changing of the body colour of chameleon to match the colour of the foliage on which it is resting
D
the release of phosphorus into the phloem of a plant growing in a phosphorus-deficient soil
correct option: d

Homeostasis is a living organism's way of maintaining a stable internal environment even in the event of external environmental changes. When the plant keeps supplying phosphorus to the phloem even in the case of a deficiency in the soil, it maintains a steady balance on its inside irrespective of the lack in the soil.

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14

Ultrafiltration in the kidney takes place in the

A
Renal vein
B
Medulla
C
Loop of Henle
D
Bowman's Capsule
correct option: d

The fine structure of the glomerulus and Bowman’s capsule facilitate ultrafiltration. It is the non-specific filtration of the blood under high pressure and occurs in the Bowman’s capsule of the nephron.

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15

The thyroid gland is found at the base of the

A
Midbrain
B
Kidney
C
Neck
D
Liver
correct option: c

The thyroid gland is an endocrine gland located at the base of the neck.

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16

Which of the following statements about the response of neurones to stimulus is correct?

A
Neurons respond to stimulus of any strength
B
Neurons respond to all stimuli applied in rapid succession
C
Neurons respond more rapidly during the absolute refraction period
D
Intensity of stimulus must reach a threshold value before the neurons can be excited
correct option: d

Each neuron has a threshold that must be met before an action potential travels the length of the neurons axon. In other words, the neurons don't just begin to act immediately, there is a threshold value where the intensity of the stimulus must get to in order to yield a response from the neuron. This is why you can consciously pinch your self and not feel anything serious but when it is unconscious, it gives you serious pain.

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17

Which of the following practices may lead to infection of the eye? Use of

A
contact lenses
B
convex lenses
C
biconcave lenses
D
concave lenses
correct option: a

Contact lenses have a way of causing infections to the eyes at some point. It can cause a lack of oxygen since they are worn directly in the eye, especially if worn for long periods at a stretch.

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18

The structures for gaseous exchange in breathing roots are

A
stomata
B
lenticels
C
cuticle
D
mitochondria
correct option: b

Breathing roots, also known as pneumatophores, have portions of the root which grow upward until they project some centimetres above the low-tide level. They have small openings called lenticels in their bark so that air can reach the rest of the plant’s root system.

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19

The diagram above is an illustration of the life cycle of an insect. The adult fly in this cycle is called

A
Housefly
B
Butterfly
C
Cockroach
D
Mosquito
correct option: b

From the diagram, the larva is a caterpillar, hence, the adult is called a Butterfly.

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20

In the diagram above, the larva is also known as

A
Nymph
B
Caterpillar
C
Maggot
D
Chrysalis
correct option: b

The diagram is the life cycle of a butterfly whose larva is called Caterpillar.

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