Page 1 - Cl8-Bio_CBQ_Micro organisms Friend & Foe (1)

SAI International School
Subject – Biology, Class-VIII
Topic- Microorganisms: Friend and Foe
Competency Based Worksheet

SL. No Question
1. A scientist discovers a new fungus that grows rapidly on fruits and spoils them. How can
this microorganism be classified?
(a) Friendly, because it grows quickly
(b) Harmful, because it causes food spoilage
(c) Friendly, because it is a natural organism
(d) Neutral, as it doesn't affect humans directly
2. If antibiotics kill bacteria, why should they not be taken without a doctor’s advice?
(a) They are too expensive
(b) They might kill viruses instead
(c) They can kill useful bacteria in the body and cause resistance
(d) They always work, so advice is not needed
3. Which one best explains why vaccines are effective?
(a) They kill all microorganisms in the body
(b) They introduce weakened microbes that help the body produce immunity
(c) They provide antibiotics to fight infection
(d) They change the body’s temperature
4. After a flood, several people in a village fell ill due to contaminated water. Identify the
type of microorganisms that could cause such diseases.
(a) Cholera and Typhoid
(b) chicken pox and cholera
(c) Tuberculosis and Typhoid
(d) Polio and Measles.
5. Eating curd every day will help in reducing cholesterol levels, thus lowering the risk of
high blood pressure and hypertension. It helps in keeping the level of cholesterol
balanced and the heart healthy. Do you know in making curd a microorganism plays the
most significant role? If yes, then identify –
(a) Bacteria Salmonella
(b) Bacteria Bacillus
(c) Bacteria Vibrio
(d) Bacterial Lactobacillus
6. A student in a village area observed a few green patches on the boundary wall of his
school. He asked his teacher about the green patches. His teacher clarified the doubt of
that student. Now he is able to recognize the group of organisms belonging to the
green patches as
(a) A type of Bacteria
(b) A type of Algae
(c) A type of Virus
(d) A type of Fungus
7. Arrange the following boxes in the correct sequence to make a complete nitrogen cycle.