Why all the crops do not grow in the same season?

Why do frogs croak in the rainy season ?

Fill in the blanks (a) Pigeon pea is a good source of "_________" (b) Berseem is an important "_________" Crop. (C) the crops which are grown in rainy season are called "_________" crops. (d) "_________" are rich in vitamins. (e) "_________" crop grown in winter season.

Explain why does the southern parts of India grow the same crops thrice a year?