Question

Insect-pollinated flowers have sticky pollen grains

Answer 1

In insect pollinated flowers the pollens are rough and sticky.Whenever an insect sits on any flower, the pollen grains being rough and sticky, are attached to antennae legs, wings of an insect and are thus carried to other flowers.

Answer 2

Cross pollination through insects takes place when the insect sits on the flower and the pollen grains stick to their legs. Thus the pollen grains being sticky make it more viable to stick to the insects body.