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.
The combination of genes expresses itself in the traits of a person. There are 23 pairs of chromosomes in a single cell of a fertilized egg. On each pair of chromosomes, two genes -- one that is dominant and one that is recessive -- are present. The combination determines the trait of a person.