“Ozone Hole” is a _____________

The correct answer is: A. Hole in the atmosphere.

An ozone hole is a thinning of the ozone layer in Earth’s stratosphere. The ozone layer contains high concentrations of ozone (O3) relative to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth’s atmosphere as a whole is about 0.3 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 20 to 30 kilometers (12 to 19 mi) above Earth, although its thickness varies seasonally and geographically.

The ozone layer is important because it absorbs most of the Sun’s ultraviolet radiation. This radiation can cause skin cancer and other health problems, and it can also damage plants and animals. The ozone layer is also important for the Earth’s climate, as it helps to regulate the amount of heat that is trapped in the atmosphere.

The ozone hole was first discovered in the 1980s. It is caused by human activities, such as the release of chlorofluorocarbons (CFCs) into the atmosphere. CFCs are chemicals that were once widely used in refrigerators, air conditioners, and other products. They are very stable and do not break down easily in the atmosphere. When they reach the stratosphere, they are broken down by ultraviolet radiation, and the chlorine atoms that are released react with ozone molecules, destroying them.

The Montreal Protocol, an international treaty, was signed in 1987 to phase out the production and use of CFCs. As a result of the Montreal Protocol, the ozone hole has been slowly shrinking. However, it is still not fully repaired, and it is expected to take several decades for the ozone layer to return to its pre-1980s levels.

The other options are incorrect because:

• Option B is a description of the ozone hole, not the ozone hole itself.
• Option C is a term used to describe the Earth’s water, not the ozone hole.
• Option D is a term used to describe the lowest layer of the Earth’s atmosphere, not the ozone hole.