506: A person stood alone in a desert on a dark night and wanted to reach his village which was situated 5 km east of the point where he was standing. He had no instruments to find the direction but he located the polestar. The most convenient way now to reach his village is to walk in the
(a) direction facing the polestar
(b) direction opposite to the polestar
(c) direction keeping the polestar to his left
(d) direction keeping the polestar to his right
507: Ultrafiltering units of kidney are known as:
(a) Nephron
(b) Glomerulus
(c) Vena Cava
(d) Tubule
508: Total internal reflection can take place when light travels from
(a) diamond to glass
(b) water to glass
(c) air to water
(d) air to glass
509: Other than poaching, what are the possible reasons for the decline in the population of Ganges River Dolphins?
1. Construction of dams and barrages on rivers.
2. Increase in the population of crocodiles in rivers.
3. Getting trapped in fishing nets accidentally.
4. Use of synthetic fertilizers and other agricultural chemicals in crop-fields in the vicinity of rivers.
Select the correct answer using the code given below :
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1, 3 and 4 only
(d) 1, 2, 3 and 4
510: Which one of the following suggested that the Governor should be an eminent person from outside the State and should be a detached figure without intense political links or should not have taken part in politics in the recent past?
(a) First Administrative Reforms Commission (1966)
(b) Rajamannar Committee (1969)
(c) Sarkaria Commission (1983)
(d) National Commission to Review the Working of the Constitution (2000)