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.
Once water molecules collect they mix with the other atmospheric ingredients to form a cloud. slide 4 of 9. Dust Particles Dust particles are a necessary atmospheric ingredient in cloud formation. Unless relative humidity exceeds 100%, dust particles must be present in order for a cloud to form. This dust can come from a number of sources such as ocean sea spray, volcanoes, fires or cars.