There are almost as many different types of four-wheel-drive systems as there are four-wheel-drive vehicles. It seems that every manufacturer has several different schemes for providing power to all of the wheels.
Most mammals have only one pair of sex chromosomes in each cell. Males have one Y chromosome and one X chromosome, while females have two X chromosomes. In mammals, the Y chromosome contains a gene, SRY, which triggers embryonic development as a male. The Y chromosomes of humans and other mammals also contain other genes needed for normal sperm production.
23. Gametes (eggs and sperm) need to have half the normal chromosome number OS that when they combine the create a normal (or diploid) cell with 46 chromosomes.ince humans have 46 chromosomes in their body cells, male gametes have half as many, or 23 chromoso â¦ mes. (Assuming you're asking about male humans). 2 people found this useful. Answered.