Question

the main, or central, idea of the passage is scientists are trying to address damage to reefs by breeding corals that are able to survive in warmer and more acidic oceans. how does the detail in bold develop the main idea?
coral reefs are one of earths most crucial ecosystems, supporting over seven thousand species of marine animals. however, coral reefs are severely threatened by environmental pressures such as rising global water temperatures, the increasing acidity of the oceans, and pollution. more than half of earths coral reefs have been lost since 1950. the rapid depletion of reef habitats has led marine biologists to use genetics to intervene. using an approach called \assisted evolution,\ a team of researchers from the university of hawaii has studied how to breed corals with mutations that make them better able to withstand changing ocean conditions. if these hardier corals can be placed among wild corals, scientists hope that global reefs may be able to adapt to and survive environmental pressures as they continue to intensify.
it acknowledges a flaw in the scientists approach.
it clarifies a misunderstanding about coral reefs.
it emphasizes the urgency of coral reef depletion.

Explanation:

The passage focuses on scientists trying to address reef damage by breeding hardy corals. The bold - faced detail about the rapid depletion of reef habitats since 1950 emphasizes how urgent the situation is for coral reefs and thus the need for the scientists' intervention.

Answer:

It emphasizes the urgency of coral reef depletion.