What is biodiversity?

The correct answer focuses on the concept of biodiversity as the variety of life forms present within a specific habitat or ecosystem. Biodiversity encompasses not just the number of different species, including plants, animals, fungi, and microorganisms, but also the genetic diversity within those species and the variety of ecosystems that support them. This diversity is crucial for ecosystem resilience, productivity, and the overall functioning of the environment. It contributes to ecosystem services such as pollination, nutrient cycling, and climate regulation, which are vital for the health of the planet and human well-being.

The other choices do not fully capture the essence of biodiversity. While the number of ecosystems in a region relates to biodiversity, it does not define it. The total amount of biomass refers to the mass of living biological organisms in a given area, which is a separate ecological measure. Lastly, focusing solely on the study of animal life ignores the rich diversity of plant and microbial life that is integral to biodiversity. Thus, choice A accurately encompasses the broad and inclusive concept of biodiversity.