Final answer:
UVB radiation is known as "burning rays" because (a) it causes sunburn and increases the risk of skin cancer, due to its ability to damage DNA molecules in skin cells.
Step-by-step explanation:
UVB radiation is referred to as "burning rays" because UVB wavelengths are primarily responsible for causing sunburn of the skin as well as increasing the risk of skin cancer. When UVB radiation penetrates the skin, it can damage the DNA molecules within skin cells, potentially leading to cancerous mutations. The ozone layer typically absorbs a significant amount of UVB radiation, but due to ozone depletion, more UVB rays can reach the Earth's surface, presenting a hazard to human health.
Sunscreen is important as it helps protect the skin from the immediate damage caused by UVB rays and can also reduce the long-term risk of developing skin cancer. Moreover, UVB radiation can also cause other issues such as cataracts. Hence, the correct answer is: (a) UVB wavelengths cause burning of the skin as well as cancer.