The best answer is b. 4
The human heart has four chambers - two atria and two ventricles.
1. Right atrium - receives oxygen-poor blood from the body and pumps it to the right ventricle.
2. Right ventricle - pumps oxygen-poor blood to the heart.
3. Left atrium - receive oxygen - rich blood from the lungs.
4. Left ventricle - pumps oxygen rich blood to the body.
The heart is a muscular organ. It is about the size of a closed fist. It is located in the thoracic cavity. It is protected by the rib cage and is the major organ of the circulatory system.
Answer:
the male reproductive cell is called a(n) sperm
the female reproductive cell is called a(n) egg
when the male and female cells join during fertilization, a(n) embryo forms
Explanation
During a males life, the sperm forms. During a females life, the egg forms. When a man and a woman fall in love, the reproduce, causing the sperm and egg join to form a embryo
Answer:
preparation, environmental controls, and contact guidelines
Explanation:
Visual, mathematical, and computer models.