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SAI International School
Subject- Biology, Class-VIII
Topic- Microorganisms: Friend and Foe
Subtopic- Nitrogen Fixation and Nitrogen Cycle
Module- 17

Home Assignment- II(Worksheet-2)

Q1. Which of the following is the carrier of dengue virus?
(a) Flies
(b) Female Anopheles
(c) Female Aedes
(d) Amoeba

Q2 Which of the following is not associated with prevention of Malaria?
(a) Use of mosquito net
(b) Keeping the surroundings clean and dry
(c) Eating covered food
(d) Spraying insecticides

Q3. Which of the following helps to improve nitrogen content of soil?
(a) Rhizobium
(b) Yeast
(c) Amoeba
(d) Paramecium

Q4. Assertion (A): Malaria can be prevented by keeping the surroundings
clean.
Reason (R): Breeding of mosquitoes can be controlled by removing the
water from the cooler, tyres and flower pot.
(a) If both Assertion and Reason are correct and Reason is the correct
explanation of Assertion.
(b) If both Assertion and Reason are correct, but Reason is not the correct
explanation of Assertion.
(c) If Assertion is correct but Reason is incorrect.
(d) If Assertion is incorrect but Reason is correct.
.
Q5. Assertion (A): Microbes help to keep the surrounding clean.
Reason (R):Microbes are used for making antibiotics and vaccines.
(a) If both Assertion and Reason are correct and Reason is the correct
explanation of Assertion.
(b) If both Assertion and Reason are correct, but Reason is not the correct
explanation of Assertion.
(c) If Assertion is correct but Reason is incorrect.
(d) If Assertion is incorrect but Reason is correct.