What type of cells are classified as haploid?

Haploid cells are those that contain only one set of chromosomes, which is half the number present in diploid cells. Germ line cells, which include sperm and egg cells, are classified as haploid because they carry only one copy of each chromosome, ensuring that when they combine during fertilization, the resulting zygote restores the diploid state.

In contrast, somatic cells are diploid, containing two sets of chromosomes—one inherited from each parent. Muscle cells also fall into the somatic category, as they encompass the tissue types that make up the muscular system and again reflect the diploid state. Stem cells, while they can have complex classifications and may be pluripotent or multipotent, are generally also diploid, possessing two sets of chromosomes.

Thus, germ line cells are correctly identified as haploid, serving a crucial role in sexual reproduction by ensuring genetic diversity through meiosis.