a) Which are a flower's bisexual parts that are not directly involved in reproduction?

 

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b) How many male gametes are produced in a pollen grain?

a) 

Parts of a bisexual flower that are not directly involved in reproduction are sepals.

A unisexual flower is defined as a flower that possesses either stamens or carpels. They do not have both stamens and carpels. For example, papaya, coconut flowers, etc. Bisexual flowers are those flowers that possess both stamens and carpels. Within the same inflorescence, male and female reproductive parts are present. For example, lily rose, etc.

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b) Two male gametes are produced by each pollen grain.

The male gametophyte (pollen grain) produces two male gametes called sperm cells. On the other hand, the female gametophyte (embryo sac) contains 8 nuclei and 7 cells, among which one cell is the female gamete or the egg.