Which of the following is a characteristic of refrigerants that do not harm the ozone layer?

The correct answer is that refrigerants classified as HFCs (hydrofluorocarbons) are characterized as not harming the ozone layer. HFCs do not contain chlorine or bromine, which are the elements responsible for ozone depletion. Therefore, their chemical structure allows them to perform effectively in refrigeration applications without contributing to ozone layer damage.

Hydrocarbons, while they indeed do not deplete the ozone layer, are typically flammable and not used in certain applications due to safety concerns. The option regarding greater abundance does not necessarily define the environmental impact concerning ozone depletion; it simply refers to availability. Lastly, the claim that they require less maintenance does not relate directly to their impact on the ozone layer but rather pertains to operational considerations. Therefore, the classification of refrigerants as HFCs is a clear indicator of their ozone-friendly nature.