Question

Biological importance of ozone layer is:
A.Ozone layer stops ultraviolet rays
B.Ozone layer reduces greenhouse effect
C.Ozone layer reflects radio waves
D.Ozone layer controls ${O_2}/{H_2}O$ radio in the atmosphere.

Answer 1

Hint: We know that the ozone layer or ozone shield is a portion of the stratosphere of the Earth that absorbs several harmful radiation of the Sun. "Ozone holes" are popular names for parts of damage to the ozone layer. Ozone is a trace gas found in the atmosphere.Ozone layer is also present at Venus.

Complete answer:
We have to remember that the one layer of the stratosphere is the ozone. The second layer of the atmosphere of the Earth is the stratosphere. The warmth of the stratosphere increases as we move higher because intense ultraviolet radiation from the sun is absorbed by the ozone gases present in the upper layers.
We must remember that the ozone molecules made of three joined oxygen atoms. Ozone is formed by striking ordinary two molecules of oxygen, breaking them to separate oxygen atoms (atomic oxygen), which combines with unbroken oxygen to form ozone.
We have to know that the ozone is good at trapping a type of radiation known as ultraviolet radiation, or UV light, that could enter protective layers of organisms such as skin, damaging molecules of DNA present in plants and animals. Ninety eight percent of the harmful ultraviolet rays are absorbed by the ozone layer.
Therefore, the option (A) is correct.
Ozone layer does not reduce the greenhouse effect. Greenhouse effect is caused by gases like methane and carbon dioxide.
Therefore, the option (B) is incorrect.
The Ozone layer does not reflect radio waves. Radio waves are reflected by the ionosphere.
Therefore, the option (C) is incorrect.
The Ozone layer does not control ${O_2}/{H_2}O$ radio in the atmosphere. Therefore, the option (D) is incorrect.
Therefore, the option (A) is correct.

Note:
We must remember that the chemicals named as Chlorofluorocarbons thins the ozone layer. The molecule of chlorofluorocarbon contains carbon, fluorine, and chlorine. They are mostly products of plastic and refrigerants. Nitric oxide, hydroxyl, nitrous oxide, atomic chlorine and atomic bromine also cause depletion of the ozone layer.