The term<unk>  is derived from the word<unk> os (meaning "seed") and refers to the male reproductive cells.<unk>  cells are the smaller gametes involved in fertilization. In these types of sexual reproduction, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or<unk>  cell. A uniflagellar<unk>  cell that is motile is also referred to as<unk> atozoon, whereas a non-motile<unk>  cell is referred to as<unk> atium.<unk>  cells cannot divide and have a limited life span, but they can fuse with egg cells during fertilization to form a totipotent zygote with the potential to develop into a new organism.
The<unk> atozoa of animals are produced through<unk> atogenesis inside the male gonads (testicles) through meiosis.<unk>  cells in algal and many plant gametophytes are produced in male gametangia (antheridia) through mitosis. In flowering plants,<unk>  nuclei are produced inside pollen.
Sperm
Gametocyte
Ovum
Oocyte
Granulocyte
Cell 
Speculum
Blood cell