Human Body Systems

4. The male reproductive cell, produced in the testes, which can fertilize a female egg.
6. The period of life between childhood and adulthood, which includes puberty and significant social, emotional, and physical development.
7. The biological process of removing metabolic waste products (like urea, salts) and excess materials from the body.
12. The female reproductive cell (ovum), produced in the ovaries, which can be fertilized by a sperm.
13. The outermost, protective layer of the skin.
14. The largest organ of the body; it acts as a protective barrier, regulates temperature, and allows for the sense of touch.
15. One of two bean-shaped organs that filter waste products and excess water from the blood to form urine.

1. The hollow, muscular female organ where a fertilized egg implants and a fetus develops during pregnancy.
2. The female reproductive organ that produces eggs (ova) and the hormones estrogen and progesterone.
3. A chemical messenger produced by glands in the body. It travels in the bloodstream to regulate growth, development, and other functions (e.g., testosterone, estrogen).
5. The stage of human development when the body becomes capable of sexual reproduction, marked by physical and emotional changes.
8. The process in the kidney where useful substances (like water, glucose, and salts) are taken back from the filtrate into the bloodstream.
9. The muscular, sac-like organ that stores urine produced by the kidneys before it is excreted from the body.
10. The male reproductive organ that produces sperm and the hormone testosterone.
11. The microscopic filtering unit inside the kidney where blood is cleaned and urine is formed.