Question

read the passage. rethinking coral reefs 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 entire reefs may be able to adapt to and survive environmental pressures as they continue to intensify. what is the main, or central, idea of the passage? scientists are trying to address damage to reefs by breeding corals that are able to survive in warmer and more acidic oceans. \assisted evolution\ studies the kinds of genetic mutations that make organisms less susceptible to changing environmental conditions. the preservation of coral reefs is important because thousands of marine species depend on the reef ecosystem for survival.

Explanation:

The passage first emphasizes the importance of coral reefs and the threats they face. Then it focuses on how scientists are using "assisted evolution" to breed hardier corals to help reefs adapt to environmental pressures. The main - idea should capture this solution - oriented approach to reef damage. The first option best does this. The second option is too focused on the concept of "assisted evolution" alone. The third option only mentions the importance of coral reefs without the solution aspect.

Answer:

Scientists are trying to address damage to reefs by breeding corals that are able to survive in warmer and more acidic oceans.