Which one is surrounded by callose wall
1. Male gamete
2. Pollen grain
3. Egg
4. Microspore mother cell

Which of the following is not a character of anemophilous flowers?
1. Pollens are light and non sticky
2. Stamens are well exposed
3. Have large, often feathery stigma
4. Have multiple ovules in each ovary

Pollen tablets are available in the market for:
1. In vitro fertilization
2. Breeding programmes
3. Supplementing food
4. Ex situ conservation

Pollen grains can be stored for several years in liquid nitrogen having a temperature of        
1. - 196$°$C
2. - 80$°$C
3. - 120$°$C
4. - 160$°$C