Biodiversity refers to what?

• A. The number and variety of plant and animal species on Earth, including genetic variation within species.
• B. Only the number of ecosystems.
• C. The total mass of all living organisms.
• D. The variety of weather patterns.

Answer: (A)

Biodiversity is about the variety of life across the planet, including how many different plant and animal species exist and the genetic differences within those species. This combination—how many species there are and how much genetic variation each species has—explains why ecosystems can be resilient and continue to function even as conditions change. It’s not just about counting ecosystems, the total mass of living things, or how weather varies; those relate to other ideas like ecosystem diversity, biomass, or climate, but they don’t capture the full idea of biodiversity. So the best description is the one that includes both the number and variety of species plus the genetic variation within those species.