Final answer:
Habitat destruction is the main reason for the loss of biodiversity worldwide. This occurs when natural habitats are altered to such an extent that they can no longer support the species they originally sustained. Human activities such as farming, logging, fishing, and construction contribute to habitat destruction.
Step-by-step explanation:
The main reason for the loss of biodiversity is habitat destruction through various activities of humankind, including farming, logging, fishing, and the construction of roads and buildings. Habitat destruction occurs when a natural habitat, such as a forest or wetland, is altered so dramatically that it no longer supports the species it originally sustained. This leads to a loss of biodiversity and is considered the most important driver of species extinction worldwide.