What role do vitamins play in the body, and why can’t they be synthesized by the body?
What role do vitamins play in the body, and why can’t they be synthesized by the body?

What role do vitamins play in the body, and why can’t they be synthesized by the body?
How do dietary minerals function as essential chemical elements in the body?
What are essential nutrients, and why must they be included in the diet?
What are the risks and benefits associated with scientific research in the context of environmental effects on male fertility, particularly related to the release of steroids used in contraceptive pills?
Annotate diagrams of mature sperm and egg cells to indicate their structure and function in fertilization.
Annotate a diagram of the seminiferous tubule and ovary to indicate the stages of spermatogenesis and oogenesis.
How does the 38-week pregnancy in humans compare to the development of young at birth in other mammals, particularly in terms of size and gestation period?
How does positive feedback involving estrogen and oxytocin mediate birth?
How do estrogen and progesterone secreted by the placenta support pregnancy once it has formed?
How does the placenta facilitate the exchange of materials between the mother and fetus, and what are some examples of substances exchanged?