Edouard van Beneden was a zoology professor at the University of Liège whose worked showed how chromosomes are organized during gamete formation or during meiosis process.
During meiosis, the chromosomes number is reduced to half so each gamete contains half of the chromosome found in somatic cell and are called haploid cells. This reduction in chromosome number is necessary to bring the correct number of chromosomes in the zygote.
During fertilization, sperms fuse with eggs to produce a single diploid cell that is known as zygote. So the zygote has 46 chromosome in which half comes from sperm and half from the egg.
The integumentary system, which includes the skin, protects the body and regulates temperature/homeostasis. It also eliminates small amounts of waste, but it does not aid in movement directly.
The result of the initial rotation of the cloud of gas and dust that condensed to form the Sun and planets. As gravity condensed the clouds, of angular momentum increased the rotational speed and flattened the cloud out into a disk.