Question

(a) Respiration is a process that is part of the carbon cycle. Use words from the list to complete the definition of the term respiration. Each word may be used once, more than once or not at all.

cells      DNA      elements      energy
enzymes                               molecules

Respiration is the chemical reactions in …………….. that break down nutrient …………….. and release …………….. .

▶️Answer/Explanation

Respiration is the chemical reactions in cells that break down nutrient molecules and release energy.

(b) Fig. 4.1 is a simplified diagram of the carbon cycle. Some of the processes that take place in the carbon cycle are represented with the letters A, B, C and D.

(i) Identify all the letters that represent respiration in Fig. 4.1.

▶️Answer/Explanation

B and C

(ii) Add an arrow to Fig. 4.1 to represent photosynthesis.

▶️Answer/Explanation

An arrow should be drawn from carbon dioxide in the atmosphere to carbon in plants, indicating the process of photosynthesis.

(c) Deforestation can cause an increase of carbon dioxide in the atmosphere. Animal species living in areas where deforestation occurs are also affected. Describe two effects of deforestation on animal species.

▶️Answer/Explanation

1 Loss of habitat

2 Extinction