451: Consider the following:

Carbon monoxide
Methane
Ozone
Sulphur dioxide
Which of the above are released into atmosphere due to the burning of crop/biomass residue?

(a) 1 and 2 only

(b) 2, 3 and 4 only

(c) 1 and 4 only

(d) 1, 2, 3 and 4
Explanation:
Explanation-Burning of crop residues emits traces of carbon dioxide, methane, carbon monoxide, nitrous oxide, sulphur dioxide and particulates which affect human health.

Punjab and Haryana are both responsible for causing air pollution due to burning. These two states contribute to 48 per cent of the total emission due to paddy burning across India.

Note: The majority of tropospheric ozone formation occurs when nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs), such as xylene, react in the atmosphere in the presence of sunlight.

Source: http://www.isca.in/EARTH_SCI/Archive/v1/i1/4.ISCA-IRJES-2013-005.pdf

https://www.downtoearth.org.in/news/air/paddy-burning-ngt-orders-fine-imposition-on-erring-farmers-51698
452: The basic reason for the extraordinary sparkle of a suitably cut diamond is that

(a) it has a very high transparency

(b) it has a very high refractive index

(c) it is very hard

(d) it has well-defined cleavage planes
453: Plankton refers to:

(a) A kind of fish

(b) A submerged platform in waters

(c) Drifting of organisms in a body of water

(d) A kind of animal living under water
454: Cobalt-60 is commonly used in radiation therapy because it emits

(a) alpha rays.

(b) beta rays.

(c) gamma rays.

(d) X-rays.
Explanation:
Cobalt-60 is commonly used in radiation therapy for the treatment of cancer because it emits gamma rays.
455: The main constituents of pearl are

(a) calcium carbonate and magnesium carbonate

(b) aragonite and conchiolin

(c) ammonium sulphate and sodium carbonate

(d) calcium oxide and ammonium chloride