CBSE Class 8 Science The Invisible Living World: Beyond Our Naked Eye (Class 8 NCERT New) Quiz 8

1. Yeast produces a small amount of alcohol during its growth, which gives the dough a slightly different smell.

A True B False

2. Write your prediction for the change in the appearance of milk in Bowl A.

A The milk in Bowl A will thicken and form curd due to the warm conditions. B The milk in Bowl A will turn blue due to the warm conditions. C The milk in Bowl A will evaporate completely due to the warm conditions. D The milk in Bowl A will freeze due to the warm conditions.

3. Write your prediction for the change in the appearance of milk in Bowl B.

A The milk in Bowl B will remain mostly unchanged or take longer to form curd due to the cold conditions. B The milk in Bowl B will immediately turn into curd due to the cold conditions. C The milk in Bowl B will boil and evaporate quickly. D The milk in Bowl B will change color to blue due to the cold conditions.

4. Write your prediction for the change in the colour of milk in Bowl A.

A The colour of milk in Bowl A may become slightly off-white as curd forms. B The colour of milk in Bowl A will turn bright red. C The colour of milk in Bowl A will become completely transparent. D The colour of milk in Bowl A will turn dark green.

5. Write your prediction for the change in the colour of milk in Bowl B.

A The colour of milk in Bowl B will remain unchanged. B The colour of milk in Bowl B will turn blue. C The colour of milk in Bowl B will turn green. D The colour of milk in Bowl B will turn yellow.

6. Fill in the blank: The bacterium that helps turn milk into curd is ___________.

A Lactobacillus B Escherichia coli C Staphylococcus D Bacillus subtilis

7. The function of Rhizobium bacteria in legume plants is:

A To fix atmospheric nitrogen into a usable form for the plant B To absorb water from the soil C To produce glucose through photosynthesis D To protect the plant from insect pests

8. Read the passage below: Microalgae are microscopic plant-like organisms that live in water, soil, air, and even on trees. They make their own food using sunlight. While doing this, they also release oxygen and produce more than half of the Earth’s oxygen supply. They are rich in nutrients and serve as a food source for many aquatic animals. Some, like Spirulina, Chlorella, and Diatoms, are also used by humans as health supplements and medicines. Microalgae also help in cleaning water and are used to make biofuel.

A Producing oxygen B Serving as food for aquatic animals C Making biofuel D Producing alcohol

9. Fill in the blank: Microalgae produce more than _______ of the Earth's oxygen supply.

A half B quarter C one-tenth D one-third

10. It is important to conserve microalgae to maintain oxygen balance on Earth.

A True B False