Question

Wind pollinated flowers produce large number of pollen grains . Why ?

Answer 1

Since the pollen grains are light weight so they fly off in large number lot of them get wasted so they produce large number of pollen grains.

Answer 2

Explanation:

Wind pollinated flowers are the kind of flowers which involves in pollination through the transfer of pollen grains from one plant to another.  For a plant which is completely dependent on wind and other forms like insects for their pollination, the pollen grains are very important.

So, they need to "produce a large number" of pollen grains for their transfer between plants when compared with the other plants. Production of large number of pollen grains increases the chance for fertilization of large number of pollen grains.