Sex Chromosomes. Sex chromosomes are particular chromosomes that are involved in determining the sex of an organism. In the cells of humans and many other organisms the sex chromosomes consist of a pair of chromosomes called the X and Y chromosomes. The X and Y chromosomes were first discovered in beetles by Nettie Stevens in 1906.
What makes up household dust: 1  Dead skin cells. 2  Live dust mites. 3  Dead dust mites and dust mite feces.  Pollen and 1  allergens. Combustion byproducts (smoke)  Clothing 1  fibers. Pesticide residue.
This is true both for fine particles (PM2.5) and for coarse and fine particles combined (PM10). However, near roads mineral dust is also a main component of PM10. On days when the levels of particulate matter in the air are high (PM10 exceeds 50 Âµg/m3), nitrate is also a major component of both PM10 and PM2.5.