Question

19. How can a decline in the population of freshwater mussels affect the ecosystem?

a) It will always lead to an increase in aquatic plant growth.
b) It can improve water quality by reducing filter-feeding activity.
c) It may disrupt the food chain and reduce biodiversity.
d) It has no impact on the ecosystem as mussels are small organisms.

Answer 1

c) It may disrupt the food chain and reduce biodiversity.

Freshwater mussels play a significant role in freshwater ecosystems as filter feeders, helping to improve water quality and serve as a food source for various species. A decline in their population can adversely affect these interactions, disrupting the food chain and leading to reduced biodiversity.

Answer 2

20. What is the main dietary source of herbivores in an aquatic ecosystem?
a) Other herbivores
b) Decomposed organic matter
c) Carnivores
d) Algae and aquatic plants

Answer 3

d) Algae and aquatic plants

Herbivores in an aquatic ecosystem primarily feed on algae and aquatic plants, which serve as their main dietary source.

Answer 4

21. Which layer of the Earth’s atmosphere does weather and climate change occur?
a) Thermosphere
b) Troposphere
c) Stratosphere
d) Mesosphere

Answer 5

b) Troposphere

Weather and climate change primarily occur in the troposphere, which is the lowest layer of the Earth's atmosphere.