851: Why camphor disappears when kept on a plate?

(a) It sublimes

(b) It reacts with the metal of the container

(c) It reacts with the gases of the air

(d) None of the above
852: A merchant wants a gross profit of 25 per cent on the sales. Thus the percentage he should add to the cost price will be:

(a) 25 per cent

(b) 33 per cent

(c) 66 per cent

(d) 75 per cent
853: Who among the following is a Hindustani classical singer ?

(a) Geeta Chandran
(b) Gangubai Hangal
(c) Swapnasundari
(d) Leela Samson
854: With reference to the food chains in ecosystems, which of the following kinds of organism is / are known as decomposer organism / organisms?

1. Virus

2. Fungi

3. Bacteria

Select the correct answer using the codes given below.

(a) 1 only
(b) 1 and 3 only
(c) 2 and 3 only
(d) 1, 2 and 3
855: Which one of the following is the correct sequence of a food chain?

(a) Diatoms-Crustaceans-Herrings.
(b) Crustaceans-Diatoms-Herrings.
(c) Diatoms-Herrings-Crustaceans.
(d) Crustaceans-Herrings-Diatoms.