621: Which of the following can be found as pollutants in the drinking water in some parts of India?
1. Arsenic
2. Sorbitol
3. Fluoride
4. Formaldehyde
5. Uranium
Select the correct answer using the codes given below.
(a) 1 and 3 only
(b) 1, 3 and 5 only
(c) 2, 4 and 5 only
(d) 1, 2, 3, 4 and 5
622: Which one of the following is the appropriate reason for considering the Gondwana rocks as most important of rock systems of India?
(a) More than 90% of limestone reserves of India are found in them
(b) More than 90% of India's coal reserves are found in them
(c) More than 90% of fertile black cotton soils are spread over them
(d) None of the reasons given above is appropriate in this context
623: In a wooden box there are 3 red and 4 black balls. If two balls are taken out Simultaneously (without looking at them), then the probability of both the balls being red is
(a) Zero
(b) 1/7
(c) 2/7
(d) 3/7
624: Seven men, A, B, C, D, E, F and G are standing in a queue in that order. Each one is wearing a cap of a different colour like violet, indigo, blue, green, yellow, orange and red. D is able to see in front of him green and blue but not violet. E can see violet and yellow, but not red. G can see caps of all colours other than orange. If E is wearing an indigo coloured cap, then the colour of the cap worn by F is
(a) blue
(b) violet
(c) red
(d) orange
625: Consider the following crops :
1. Cotton
2. Groundnut
3. Maize
4. Mustard
Which of the above are Kharif crops?
(a) 1 and 2
(b) 1, 2 and 3
(c) 3 and 4
(d) 1, 2, 3 and 4