Questions: A "biodiversity hotspot" is an area on Earth in which there has been a significant decline in biodiversity. Much of the biodiversity decline is attributed to loss of vegetative habitats. About what percent of natural vegetation has been lost within most biodiversity hotspots?

The answer is the second one (98%): About 98% of natural vegetation has been lost within most biodiversity hotspots.

Explanation for each option:

1. 25%: This percentage is too low to be considered a significant decline in biodiversity hotspots. While a 25% loss is substantial, it does not reflect the severe level of habitat loss typically associated with biodiversity hotspots.
2. 98%: This is the correct answer. Biodiversity hotspots are regions that have experienced extreme loss of natural vegetation, often up to 98%. This high percentage indicates a critical level of habitat destruction, which is a defining characteristic of these areas.
3. 70%: Although a 70% loss is significant, it is not as extreme as the 98% loss that is commonly associated with biodiversity hotspots. This option underestimates the extent of habitat loss in these critical areas.

Summary: Biodiversity hotspots are regions that have experienced a significant decline in natural vegetation, with about 98% of natural vegetation lost in most of these areas. This extreme loss of habitat is a key factor contributing to the decline in biodiversity within these hotspots.