One-celled animal-like organisms found in decayed materials and contaminated watera. protozoab. spirillac. virusesd. fungi

A) Protozoa

Explanation:

Protozoa are the one celled organisms which belong to kingdom Protista and they are animal-like (named as protozoa). Moreover, they host dead organic matter and live in contaminated water.

Spirilla is bacteria which is not animal-like.

Viruses are non-living so they are not organisms.

Fungi is not animal-like or single celled.

both male and female gametes are produced by meiosis of the germ cells. therefore, both male and female gametes are haploid. one male and one female gamete unite during the fertilization to form the diploid zygote. in seed bearing plants, pollen grain is the male gametophyte, which produces sperm cells.