Functional megaspore in an angiosperm develops into an

Crassinucellate ovule shows

Entry of pollen tube with two male gametes and tube nucleus through micropyle, is

They are dominant pollinator for pollination

What is the ratio of equational divisions that take place in Cycas and angiosperms respectively leading to the formation to male gametes from pollen grains?

Transfer of pollen grains from the anther to the stigma of another flower of the same plant is called