Viability of pollen grains depends on
a)	Temperature	b)	Humidity	c)	Both (a) and (b)	d)	Pressure

(c)

The period in which the pollen grains remain viable is highly variable. It depends on the temperature and humidity. In some cereals such as rice and wheat, the pollen grains loose viability with in 30 minutes of their release and in some members of Rosaceae, Leguminosae and Solanaceae, they maintain variability for months