161: With reference to 'fly ash' produced by the power plants using coal as fuel, which of the following statements is/are correct?
1. Fly ash can be used in the production of bricks for building construction.
2. Fly ash can be used as a replacement for some of the Portland cement concrete.
3. Fly ash is made up of silicon dioxide and calcium oxide only, and does not contain any toxic elements.
Select the correct answer using the code given below.
(a) 1 and 2
(b) 2 only
(c) 1 and 3
(d) 3 only
162: Radio carbon dating process is used to know the age of:
(a) Fossils
(b) Plants
(c) Rocks
(d) All of these
163: Which one of the following types of micro-organisms is most widely used in industries ?
(a) Bacteria
(b) Bacteria and fungi
(c) Bacteria and algae
(d) Bacteria, micro-algae and fungi
Explanation:
Bacteria, micro algae and fungi are employed widely in Industrial production of Antibodies, Insulin, Citric acid, alcohol etc.
164: Which one of the following reflects back more sunlight as compared to other three ?
(a) Sand Desert
(b) Paddy crop land
(c) Land covered with fresh snow
(d) Prairie land
Explanation:
The albedo of an object is a measure of how strongly it reflects light from light sources such as the Sun. Snow have a very high albedo and can be as high as 0.9. Because trees tend to have a low albedo removing forests would tend to increase aibedo and thereby could produce localized climate cooling. dry sand have low albedo (0.35) as compare to snow.
Sand desert (20 - 30%), prairie grassland (25%), Land covered with fresh snow (85%) and Paddy crop land (20-25%).
165: In which organ of the human body are the lymphocyte cells formed?
(a) Liver
(b) Long bone
(c) Pancreas
(d) Spleen
Explanation:
Lymphocytes are manufactured in the bone marrow and multiply in the Thymus and Spleen. They circulate in the blood stream, penetrating the walls of blood capillaries to reach the cells of the tissues. Nodes at various points in the lymphatic network act as stations for the collection and manufacture of lymphocytes, they may become enlarged during an infectious disease.