immune system, n the group of organs, cells, and chemicals that protect the body from harmful viruses, bacteria, and abnormal cells. It includes bone marrow, proteins, the thymus, the spleen, the lymphocytes, and other white blood cells.
50% from each parent: one allele in each gene, each parent, for a total of two. 2 people found this useful. Edit. Share to: 1  College Admission Interview Dos and Don'ts Some colleges offer applicants the opportunity to interview on campus or close to home.
When a mature sperm cells ultimately unites with a mature egg (which also has only one of the pair for each of the 23 chromosomes) the resulting fertilized egg then has 23 pairs of chromosomes (one of each pair from the father and one of each pair from the mother).