Ontario Grade 9 Science Practice Exam 2025 – Complete Study Resource

Biodiversity refers to the variety of life in a particular habitat or ecosystem. This concept encompasses not just the number of different species present but also the genetic diversity within those species and the various ecosystems themselves. High biodiversity indicates a rich tapestry of life forms — from plants to animals and microorganisms — which contributes to the resilience and stability of ecosystems.

For example, a forest with many different species of trees, plants, animals, and microorganisms exhibits high biodiversity, whereas a monoculture, where only one species is grown, has low biodiversity. A rich biodiversity contributes to ecological processes such as pollination, nutrient cycling, and habitat creation, which are crucial for the function and sustainability of the environment.

The other options touch on aspects related to living organisms or ecosystems but do not capture the holistic nature of biodiversity as defined here. The total number of organisms, health of organisms, or specific traits pertain to narrower definitions and measurements that do not fully encapsulate the complex and multifaceted nature of biodiversity.