Question

which three agents Carry out pollination in flowers

Answer 1

There are two major pollination agents 

1-  Wind (anemophily) and water(hydrophily)\
2- Insects (entomophily), birds (ornithophily) and bats (chiropterophily), the latter two classified as zoophily (a group in which, occasionally, other animal species — including humans — participate as well, see vertebrate pollinators).

Answer 2

THE THREES AGENTS WHICH CARRY OUT POLLINATION ARE AS FOLLOWS:

1] WATER POLLINATION

2] WIND POLLINATION 

3] INSECT POLLINATION