Summative Practice Chapter 3 – Question 1 & 2 (Form 5 Biology Textbook Exercise and Answer)

Question 1:
A farmer uses NPK fertiliser for his chili crops. NPK fertiliser contains nitrogen, phosphorus and potassium elements which are important nutrients for crop growth and also contains micronutrients needed by plants.

(a) In your opinion, what are the micronutrients contained in the fertiliser?

(b) Explain the functions of nitrogen, phosphorus and potassium elements towards chili plants.

(c) After using the fertiliser several times, the farmer found that the leaves of the chili plants were turning darker green and the plant stem was becoming weaker.
(i) What caused these plants to undergo such abnormal situation?
(ii) Suggest one solution to overcome the situation.

Manganese, Iron, Boron, Chlorine, Zinc and Nickel

Nitrogen stimulates the development of leaf growth. Phosphorus is important for healthy development of root. Potassium encourages the development of flowers and fruit and stimulates the growth of large and long chilies.

The chilli plant received excessive fertiliser especially nitrogen.

Reduce the frequency of fertilising

Question 2:
Mrs. Rodiah uses a vase, brick shards, charcoal shards, and coconut fibres to grow an epiphytic orchid plant. The orchid plant is placed at a corner in her house.

(a) What is meant by epiphytic orchid plant?

(b) Why does Mrs. Rodiah use coconut fibres to plant the orchid?

(c) In your opinion, what is the main factor that needs to be considered by Mrs. Rodiah before placing the orchid plant at the corner? Explain.

(d) Why does Mrs. Rodiah not plant the orchid directly into the ground? Give suitable reasons.

Epiphytic orchid plants refer to orchids that live on other plants which are the hosts. Epiphytic orchid plants obtain their nutrients by synthesising their own food without harming their hosts.

The coconut husks can retain water for the orchid plants. Their roots can hold the husks as a support. The husks can also provide aeration for the respiration of the roots.

Source of light. The orchid plants require light for photosynthesis but cannot be exposed to direct sunlight.

The orchid’s roots need a medium that can improve the drainage and aeration better than soil.
If it is planted directly into the ground, the roots may be rotted because of the excessive water.

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