What characteristic does a haploid cell have?

A haploid cell is characterized by containing half the number of chromosomes compared to a diploid cell. In humans, for instance, diploid cells have 46 chromosomes (23 pairs), meaning haploid cells, such as sperm and egg cells, contain only 23 chromosomes. This reduction is crucial for sexual reproduction because it allows for the restoration of the full chromosome number upon fertilization, when two haploid cells combine to form a zygote with a diploid set of chromosomes.

In contrast, other characteristics listed in the question do not apply to haploid cells. For instance, the assertion of a full set of chromosomes pertains to diploid cells, while claiming that a haploid cell is identical to a zygote is misleading, as a zygote is a diploid cell formed after the fusion of two haploid cells. Similarly, defining a haploid cell as diploid is inherently contradictory, given that the terms represent distinct chromosome configurations. Understanding these distinctions is fundamental to grasping the concepts of cellular division and sexual reproduction in biology.