Question

short for chlorofluorocarbons, cfcs are chemical compounds. scientists developed cfcs to replace toxic elements used in refrigeration. cfcs started being popularly used in the early twentieth century. these were used in refrigeration units and aerosol cans. at that time, it was not known that cfcs combine with ozone in our atmosphere and weaken the ozone layer. the ozone layer is important to earth in protecting it from the ultraviolet rays of the sun. because the ozone layer is weakened by cfcs, more living beings on earth are being exposed to the strong ultraviolet rays. the use of cfcs has declined. however, because it has remained in the atmosphere for nearly a century, much damage has been done to the ozone layer.

the passage is organized using the structure of

a. compare/contrast.

b. cause/effect.

c. classification.

d. definition.

Explanation:

The passage first introduces what CFCs are and their initial use. Then it explains that CFCs (cause) combine with ozone and weaken the ozone layer, leading to more UV ray exposure and ozone layer damage (effects). It shows a cause - effect relationship. Option A is incorrect as there's no comparison. Option C is incorrect as no classification of items is done. Option D is incorrect as it's not just defining CFCs but also explaining their impact.

Answer:

B. cause/effect