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.
Chromosomes are arrangements of genes made from DNA. Most of the chromosomes of plants and animals are arranged in pairs. The number of chromosomes varies among organisms. Humans typically have 46, a rice plant has 12, a fruit fly, 4. During human reproduction, both the egg and sperm donate 23 chromosomes to the fertilized egg, the zygote, for a total of 23 pairs. Each pair of chromosomes has one allele from each parent for every gene.