Is it simply the nectar which attract insects to flowers? what is it specifically that attracts insects to nectar and what do...

what is it specifically that attracts insects to nectar and what do they do with it?

and how is pollen picked up by their appetite for this nectar from blooms of flowers and plants??
Answers:    Sometimes it's nectar, sometimes it's pollen. The insects/birds guzzle or drink it. it is supplemental food.

Pollen is sticky - anything that touches it gets pollen on it - when it visit another flower, some of the pollen from a previous flower touches the stamens of the new flower, and fertilizes it.

Insects and birds are attracted to flower through scent or color. Occasionally shape. Depends on the flower, and what they are trying to attract.
no its the brightness of the petals aswell...thats one of the major functions of petals