It is a microscopic structure composed of head, neck, a middle piece and a tall.

A plasma membrane envelops the whole body of the sperm.

$\Rightarrow$ The sperm head contains an elongated haploid nucleus, the anterior portion of which is covered by a cap-like structure acrosome.

The acrosome is filled with enzymes (Hiluromdase etc) that help fertilization of the ovule.

The middle pieces of sperm possesses numerous mitochondria which produce energy for the movement of tail that facilitate sperm motility essential for fertilization.

The human male ejaculates about $200$ to $300$ million sperms during coitus of which for normal fertility atleast $60 \%$ sperms must have normal shape and size and for at least $40 \%$ of them must show vigorous motilit