476: Which one of the following soil types of India is rendered infertile by the presence of excess iron ?
(a) Desert sand
(b) Alluvial
(c) Podzolic
(d) Lateritic
477: The tropical deciduous trees shed their leaves in summer:
(a) Leaves get dried up due to the excessive heat
(b) To prevent excessive loss of water through transpiration
(c) Because rainfall is inadequate
(d) Days are longer
478: With reference to the scientific progress of ancient India, which of the statements given below are correct?
1. Different kinds of specialized surgical instruments were in common use by 1st century AD.
2. Transplant of internal organs in the human body had begun by the beginning of 3rd century AD.
3. The concept of sine of an angle was known in 5th century AD.
4. The concept of cyclic quadrilaterals was known in 7th century AD.
Select the correct answer using the codes given below :
(a) 1 and 2 only
(b) 3 and 4 only
(c) 1, 3 and 4 only
(d) 1, 2, 3 and 4
479: The best conceiving season for cows and buffaloes is:
(a) Summer
(b) Winter
(c) Spring
(d) There is no definite relationship between conceiving and season
480: The group of small pieces of rock - revolving round the sun between the orbits of Mars and Jupiter are called
(a) meteors
(b) comets
(c) meteorites
(d) asteroids