Questions 57 - 60 are based on the following passage.

    Ingestion of plastic pollution in the marine environment first drew attention in the 1970s with numerous reports of plastics found in seabirds. Given the persistent nature of plastic, it is alarming that total global estimates of plastics produced are over 8,300 million metric tons, with upwards of 12.8 million metric tons entering the ocean in 2010. The widespread occurrence of plastics in the marine environment has led to a surge of research on the potential impacts that the smaller pieces of plastics, termed microplastics (<5mm), may have on wildlife.

    Microplastics can originate from various sources including degradation of macroplastic, industrial processes, synthetic clothing, tire fibers, and personal care products. Once in the marine environment, microplastics tend to serve as a surface for microbial community growth as well as attracting pollutants. As a result, their density increases and they become more bioavailable to organisms in the environment, including benthic organisms such as scleractinian coral.

    Scleractinian corals are both phototrophic and heterotrophic feeders. Corals receive nutrition via translocation of photosynthetic products produced by zooxanthellae. Ingested microplastics by coral could potentially reduce the energetic demands needed for the calcification process by inhibiting digestion of exogenous food sources, especially in times of stress.

Source: https://doi.org/10.1016/j.marpolbul.2018.07.067

How does the author organize the passage?