Pretend that you recently turned in a paper for your science class and you have been asked to correct your problems with subject-verb agreement. Rewrite the paragraphs below, correcting any mistakes you find. In the midst of the vast, relatively unpopulated ocean, coral reefs is hotspots of biological diversity. Thousands of species is hosted within their colorful, protective borders. They support many of the fisheries that coastal communities relies upon and sustains local economies by providing billions of dollars of income from tourism.

The vibrant colors that attracts both fish and humans is the result of a symbiotic relationship between invertebrate coral polyps and colorful algae. Nutrients and protection is provided by corals to algae. In return, the algae provides the corals with sugars produced via photosynthesis.

In 1979, incidents in which coral hosts cast out their resident algae began to be reported on an unprecedented scale. This occurrence, known as coral bleaching, leave the coral a bleached white color because of the ejection of the colorful algae. Bleaching events is not necessarily lethal to corals. However, if bleaching occurs over a prolonged period of time, the coral host will eventually dies.