EGL USA is one of the largest and oldest independent gemological institutions focusing on gemstone certification and research. Originally part of an international network founded in Europe in 1974, EGL USA opened its first U.S. lab in the heart of New York's international diamond and jewelry district in 1977.
the fusion of the nucleus of a haploid sperm cell and the nucleus of a haploid egg cell, forming a diploid zygote zygote diploid cell formed when the nucleus of a haploid sperm cell fuses with the nucleus of a haploid egg cell tetrad group of four chromatids formed during prophase I of meiosis by the two sister chromatids in each of the two homologous chromosomes
Only one sperm nucleus enters the egg. The haploid sperm nucleus fuses with the haploid egg nucleus, and a fertilised egg or diploid zygote is formed. As soon as the sperm has entered the egg, the membrane of the egg changes so that no other sperm can enter. The remaining sperms, which do not fertilise the egg, eventually die. The cilia lining the oviduct sweep the zygote along the oviduct. Peristaltic movements also help move the zygote to the uterus.