696: 200 cm of rainfall, 20°C of temperature and well drained land is ideal for the cultivation of:
(a) Rice
(b) Tea
(c) Coffee
(d) Rubber
697: What is the principle by which a cooling system (Radiator) in a motor car works ?
(a) Convection
(b) Conduction only
(c) Both conduction and radiation
(d) Radiation only
698: Which one of the following is an important crop of the Barak valley ?
(a) Jute
(b) Tea
(c) Sugarcane
(d) Cotton
699: What is the common feature in insects like ant and cockroach?
(a) They bite and chew their food
(b) They live in temperate climate conditions
(c) They have cutting and sucking type of mouth parts
(d) They are social insects
700: A father is now three times as old as his son. Five years back, he was four times as old as his son. The age of the son is
(a) 12 years
(b) 15 years
(c) 18 years
(d) 20 years