Question

1. why are biologists uncertain about how many species are living on earth?

your answer

1. what is a main benefit of protecting entire ecosystems rather than individual species of plants or animals?

your answer

Explanation:

For question 21:

• Many species are in remote or hard - to - access areas (e.g., deep sea, dense rainforests).
• Some species are very small (microorganisms) and difficult to detect and count.
• New species are constantly being discovered.

For question 22:

• Ecosystems have complex interactions. Protecting the whole ecosystem ensures the survival of multiple species that depend on each other (e.g., through food webs, symbiotic relationships). It also maintains ecological processes like nutrient cycling, water purification etc. that benefit all species within the ecosystem.

Answer:

1. Biologists are uncertain because many species are in remote areas, some are very small and hard to detect, and new species are still being discovered.
2. Protecting entire ecosystems maintains complex species interactions (e.g., food webs, symbiosis) and ecological processes (e.g., nutrient cycling) that benefit all species within the ecosystem.