Protection of the body cells of mammals against ultra-violet rays of the sun is brought about by

The sun emits ultraviolet (UV) radiation that can damage the DNA in our cells. Exposure to excessive UV radiation can cause sunburn, premature aging of the skin, and increase the risk of developing skin cancer. Mammals have developed different mechanisms to protect their body cells against the harmful effects of UV radiation. One of the most important mechanisms is the production of melanin, a pigment that gives color to the skin, hair, and eyes. Melanin absorbs UV radiation and converts it into heat, which is then dissipated from the body. This process helps to prevent the UV radiation from penetrating the skin and damaging the DNA in our cells. Keratin, a fibrous protein, also provides some protection against UV radiation. It forms a protective barrier on the surface of the skin, which helps to prevent UV radiation from penetrating deeper into the skin. Sebum, an oily substance produced by the sebaceous glands in the skin, can also help to protect against UV radiation. Sebum forms a barrier on the skin's surface, which helps to prevent water loss and protect against UV radiation. Scales, on the other hand, are structures found on the skin of reptiles and fish. They provide protection against UV radiation, physical damage, and dehydration, but mammals do not have scales. In summary, the protection of body cells against UV radiation in mammals is mainly brought about by the production of melanin, which absorbs and converts UV radiation into heat, and by the presence of keratin and sebum that form protective barriers on the skin's surface.