336: Consider the following :
1. Rice fields
2.Coal mining
3. Domestic animals
4.Coal mining Wetlands
Which of the above are sources of methane, a major greenhouse gas?
(a) 1 and 4 only
(b) 1, 2 and 3 only
(c) 2 and 3 only
(d) 1, 2, 3 and 4
Explanation:
Major sources of methane are fossil fuel burning, mining, agriculture and wetlands. In an attempt to study the sources of methane in our environment, a programme to study the methane emission from the wetland lakes of Kadinamkulam, Paravur, Ashtamudy, Kayamkulam, Vembanad and Kodungalloor was taken up. The measurement results show that the methane flux from the lake is moderate. It 'is proposed to estimate methane loading into the atmosphere, from wetland environments of Kerala and to study the climate change potential of this source.
337: Assertion (A):
Scientists can cut apart and paste together DNA molecules at will, regardless of the source of the molecules.
Reason (R):
DNA fragments can be manipulated using restriction endonucleases and DNA ligases.
(a) Both A and R are individually true and R is the correct explanation of A
(b) Both A and R are individually true but R is NOT a correct explanation of A
(c) A is true but R is false
(d) A is fasle but R is true
Explanation:
'Endonucleases' and 'DNA ligases' are the tools of Genetic Engineering used in cutting and pasting of DNA regardless of the source to produce recombinant DNA's, which are utilised in production of transgenic plants and animals.
338: What is "Terminal High Altitude Area Defense (THAAD)", sometimes seen in the news?
(a) An Israeli radar system
(b) India's indigenous anti-missile programme
(c) An American anti missile system
(d) A defence collaboration between Japan and South Korea
339: Which organelle in the cell, other than nucleus, contains DNA ?
(a) Centriole
(b) Golgi apparatus
(c) Lysosome
(d) Mitochondrion
Explanation:
Mitochondrion and chloroplast are the cell organelles containing DNA other than nucleus. Hence they are called 'Semi autonomous' organelles where they can synthesize some of its essential proteins with partial dependence on 'Nucleus'.
340: The resinous substance, shellac is obtained from
(a) Crude oil
(b) The bark of a tree
(c) An insect
(d) Distillation of wood