The correct answer is D. UV radiations is injurious to plants because it causes genetic changes.
UV radiation is a type of electromagnetic radiation that has a shorter wavelength than visible light. It is found in sunlight and can also be emitted by artificial sources such as tanning beds. UV radiation can damage DNA, which is the genetic material of cells. This damage can lead to mutations, which are changes in the DNA sequence. Mutations can be harmful to plants, and can cause a variety of problems, including stunted growth, reduced yields, and susceptibility to diseases.
Option A is incorrect because UV radiation does not break phosphate bonds. Phosphate bonds are the bonds that hold together the sugar-phosphate backbone of DNA. UV radiation can damage DNA, but it does not break these bonds.
Option B is incorrect because UV radiation does not increase respiration. Respiration is the process by which cells convert food into energy. UV radiation can damage cells, but it does not increase respiration.
Option C is incorrect because UV radiation does not cause dehydration. Dehydration is the loss of water from the body. UV radiation can damage cells, but it does not cause dehydration.