NAME FORM 3
BIOLOGY END OF TERM ONE EXAMINATION
Instructions
Write your name on top of every page
This paper has pages and 15 questions please check.
Write your answers in the space provided
Answer all questions
SECTION A : 70 MARKS
1. a. Define the term sampling (1 mark)
b. State any two advantages of the quadrat method of estimating population (2 marks)
2. a. What do arrows in a food chain or food web indicate? (1 mark)
b. What occupies the bottom box in food pyramids? (1 mark)
3. Explain how the following aspects of the nitrogen cyle help in nitrogen fixation
i. Nitrifying bacteria (2 marks)
ii. Lightening (2 marks)
4. a. Figure 1. is a diagram showing the carbon cycle
i. Mention any two processes shown in the diagram that lead to increase in carbon in the atmosphere ( 2
marks)
ii. Describe the transfer of carbon from the atmosphere to an animal (3 marks)
b. Briefly explain how water is released back into the atmosphere (3 marks)
5. a. List down any two types of plant communities in fresh water ecosystem (2 marks)
b. Describe how each of the following physical factors influence the distribution of organinsms in fresh
water ecosystem
i. Light intensity (2 marks)
ii. Nutrient concentration (2 marks)
6. Briefly explain how animals are adapted to the following environments
i. Dry areas (3 marks)
ii. Cold areas (3 marks)
7. Mbinjani is a village, east of South Lunzu CDSS. The people in the village complain of the low
productivity of their livestock due to the steep slope of the area and type of vegetation in their grazing
land, twigs abd shrubs. You are approached by one of the village members, Mr Sadulo, for some advice
on the problem as a Biology student in Form 3.
a. Using your Biology knowledge, which livestock animal would you recommend to be kept in the village
(1 mark)
b. Briefly discuss three reasons for your recommendations in 7 (a) (6 marks)
8. Figure 2 below shows a type of pollution. Use it to answer questions that follow.
a. Name the type of pollution in the figure 2. above (1 marks)
b. Explain how the type of pollution named in 7 (i) above can affect life in an aquatic habitat (3 marks)
c. Explain any two impacts of climate change in Malawi (4 marks)
9. State the difference between a monocot plant and a dicot plant based on the vascular bundle
arrangement in
i. Roots (2 marks)
ii. Stem (2 marks)
10. Briefly explain any two adaptions of a leaf for photosynthesis (4 marks)
11. a. Explain two ways how sunlight energy absorbed by chlorophyll is used during light stage of
photosynthesis ( 4 marks)
b. Explain any three uses of glucose after photosynthesis ( 6 marks)
c. State the role of the following mineral elements in photosynthesis
i. Nitrogen (1 mark)
ii. Iron (1 mark)
12. Explain any three factors that affect the rate of diffusion. (6 marks)
Section B: 30 marks
Your answers should be in an essay form
13. Explain how you would estimate plant population using a quadrat method (10 marks)
14. With an aid of a well labelled diagram, explain how energy flows in an aquatic ecosystem (10 marks)
15. Explain four importance of photosynthesis (10 marks)
