In the following groups of materials, which groups contain only non-biodegradable items?
(i) Wood, paper, leather
(ii) Polythene, detergent, PVC
(iii) Plastic, detergent, grass
(iv) Plastic, bakelite, DDT
(iii)
(iv)
(i), (iii)
(ii), (iv)
(4)
Those items which cannot be acted upon by detritivores or decomposers are called as non-biodegradable. As a result, such materials are unable to degrade or decompose. They are, in some ways, an inextricable part of the environment that cannot be removed. Polythene, thermosetting plastics such as Bakelite, insecticides such as DDT, detergent, and PVC are few examples of non-biodegradable items.
UV rays are harmful to the life on earth. However, they play an important role in the upper atmosphere. Which of the following statements holds for this fact?
(i) UV rays are needed for the formation of the ozone layer in the upper atmosphere.
(ii) UV rays are less active and inside the atmosphere, they become activated due to the other atmospheric contents.
(iii) In the upper atmosphere, UV rays have less energy and are not harmful and form the part of the atmosphere.
Only (i)
Only (ii)
Only (iii)
Both (i) and (iii)
(1)
In the upper atmosphere, high energy UV rays are required for the formation of the ozone layer. Ozone prevents the entry of UV rays into the earth’s atmosphere.
