Coral reefs are ideal breeding grounds for a variety of fish and sea creatures, and coral is considered a foundation species. Un
fortunately, coral reefs are fragile ecosystems and are easily disrupted. Because coral contain calcium carbonate deposits, one situation poses a growing threat to coral as well as the many organisms that are dependent on them. That situation is A) the disappearance of certain species of fish due to overfishing.
Eliminate
B) the deposition of calcium on the reefs, due to the leaching of calcium from dead organisms.
C) over exposure to sunlight due to the relatively shallow nature of the ocean around the reefs.
D) acidification of the ocean caused by increased atmospheric carbon dioxide emissions that dissolve in water.
The correct answer is option D) "acidification of the ocean caused by increased atmospheric carbon dioxide emissions that dissolve in water".
Explanation:
According to scientific evidence, coral reefs and many organisms that have calcium carbonate shells are affected by high carbon dioxide emissions. When sea water absorbs carbon dioxide, the pH of water is reduced in what is known as acidification of the ocean. In consequence, less calcium carbonate is available for coral reefs to be used as shells, which traduces as a major threat for their populations.
Sailors had scurvy, which is caused by a lack of vitamin C. They were cured by lemon juice becaue it contains a lot of vitamin C. Vitamin C evaporates when the lemon juice is boiled so it wouldn't have the same effect.
Each molecule of DNA is a double helix formed from two complementary strands of nucleotides held together by hydrogen bonds between G-C and A-T base pairs. Duplication of the genetic information occurs by the use of one DNA strand as a template for formation of a complementary strand.
