Question(s):

QUESTION 1

1. What is classification of living things?
   [2 marks]

2. State four ways each by which the following groups of organisms are of economic importance in their habitats:
   a. Fungi
   b. Plants
   [8 marks]

3. Complete the table below by stating five major phyla of the Kingdom Animalia and give one example of each:

Phyla of Kingdom Animalia	Example

[10 marks]

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QUESTION 2

a. Complete the table below:

Element	Function in Plants	Effects of Deficiency in Plants
Iron
Molybdenum
Potassium
Copper
Nitrogen

[10 marks]

b. Name three classes of organic foods which are essential constituents in the diet of a mammal.
[3 marks]

c. State two roles each of the following structures of the digestive system in humans:

• Buccal cavity
• Duodenum
• Stomach
  [6 marks]

d. Name the end product of adding dilute hydrochloric acid to sucrose.
[1 mark]

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QUESTION 3

Relationships I, II, III, IV, and V exist among some organisms in an ecosystem. Use them to answer questions 3(a) to 3(e):

• I: Organism A grows on dead organism B.
• II: Organism C feeds on the remnants of food left by organism D without affecting organism D negatively or positively.
• III: Organism E provides shelter for organism F while organism F transports organism E towards food.
• IV: Organism G kills organism B for food.
• V: Organism H feeds on organism J, causing J a disease.

a. Name the type of relationship in I, II, III, IV, and V.
[5 marks]

b. In relationship IV, what is the biological term for each of the following:

• B:
• G:

c. Name one example each of organisms B to J.
[8 marks]

d.
(i) Name the relationship that is most beneficial to the ecosystem.
[1 mark]
(ii) Give one reason for the answer in 3(d)(i).
[1 mark]

e.
(i) Give two examples of organism A.
[2 marks]
(ii) Name the group to which organism A belongs.
[1 mark]

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QUESTION 4

a. Complete the following Punnett squares of a dihybrid cross between two rats. One has black fur (BB) and short tail (tt), and the other has brown fur (bb) and long tail (TT):

B	T	b	t

[12 marks]

b. How many of the offspring will have:

• Black fur and short tail
• Brown fur and long tail
• Black fur and long tail
• Brown fur and short tail

[4 marks]

c. If there were twenty (20) chromosomes in the leaf cell of a plant, how many chromosomes would be in each of the following cells of the plant?

• Pollen grain
• Guard cell
• Ovule
• Root cell

[4 marks]

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QUESTION 5

1. (i) What are sense organs?
   [3 marks]
   (ii) Name three sense organs that respond to the stimulus of chemicals.
   [3 marks]

2. List three animals each that exhibit the following courtship behaviors:

   • Territoriality
   • Pairing
     [6 marks]

3. (i) State one similarity between the eggs of toads and the eggs of birds.
   [1 mark]
   (ii) State three differences between the eggs of toads and the eggs of birds.
   [3 marks]

4. Complete the table below by listing four organisms involved in the nitrogen cycle and state one role each of the organisms:

Four Organisms Involved in the Nitrogen Cycle	One Role of Each Organism

[8 marks]

5. Complete the table below by naming two types of heterotrophic modes of nutrition in animals and give two examples each of organisms that carry out the modes of nutrition:

Two Modes of Heterotrophic Nutrition	Two Examples of Organisms

[4 marks]