CSEE
Biology · Paper 2B · 2021
3 questions 🇹🇿 NECTA ✓ Official NECTA answers
CSEE
🇹🇿 NECTA
✓ Official NECTA answers
Biology · Paper 2B · 2021
3 questions
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200 TZS
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Questions (3)
Section A
1.
15 marks
With reference to your experiment, answer the following questions:
(a)
Explain the changes you observe in hole A after 40 minutes.
5 mk
(a)
With reference to your experiment, what does the part labelled by letter C represent?
1 mk
(b)
Explain the changes you observe in hole B after 40 minutes.
5 mk
(b)
How does part C work in the process of osmosis?
2 mk
(c)
Explain the biological principle behind the changes observed in hole A.
8 mk
(c)
What are the observations in the holes A and B after 40 minutes?
2 mk
(d)
Account for the observations made in 1(c).
3 mk
(d)
Explain the biological principle behind the changes observed in hole B.
7 mk
(e)
Give the biological terms used for the concentrations in the holes A and B.
2 mk
(e)
Give the biological terms used for the concentrations in the holes A and B.
2 mk
(f)
Identify two osmotic activities which take place in plants by nature.
2 mk
(f)
Identify two osmotic activities which take place in plants by nature.
2 mk
(g)
Based on the observation made from the experiment, how the knowledge of osmosis can be applied in your daily life? Give two points.
2 mk
(g)
Based on the observation made from the experiment, how the knowledge of osmosis can be applied in your daily life? Give two points.
2 mk
(h)
What is the aim of the experiment?
1 mk
(h)
What is the aim of the experiment?
1 mk
(i)
How does osmosis differ from diffusion?
2 mk
(i)
How does osmosis differ from diffusion?
2 mk
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2.
15 marks
You are provided with specimens Q, R, S and T. Study them and answer the following questions:
(a)
(i) Identify each of the specimens Q R, S and T by its common name.
(ii) Why is it important for scientists to use the knowledge of classification in identification of the specimens instead of common names you used in 2(i)? Give two points
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((a)(i)
Why is it important for scientists to use the knowledge of classification in identification of the specimens instead of common names you used in 2(i)? Give two points.
2 mk
(b)
(i) Classify each of the specimens Q and R to the class level.
(ii) Give three reasons for the specimens Q and R to be placed into different classes.
6 mk
(c)
Why is the specimen R said to be economically important to human being while specimens S and Q are said to be detrimental? Give one point for each.
3 mk
(d)
What are the two observable differences between the specimens S and T at class level?
1 mk
((b)(i)
Give three reasons for the specimens Q and R to be placed into different classes.
3 mk
(c)
Why is the specimen R said to be economically important to human being while specimens S and Q are said to be detrimental? Give one point for each.
3 mk
(d)
What are the two observable differences between the specimens S and T at class level?
2 mk
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