Answer:
Superior vena cava
Explanation:
Of the two vena cava, the superior vena cava is the large vein without valves that is responsible for conveying de-oxygenated blood from the upper extremities and body (neck, chest, arm and head) above the diaphragm to the right artrium.
Although the superior vena cava is a large vein, it also short; it is about 2 cm wide and 7 cm long.
When there is an obstruction of the superior vena cava, it can result to the enlargement of the veins and could lead to chest pain and breathlessness.
Answer:
The muscular system is composed of specialized cells called muscle fibers. Their predominant function is contractibility. Muscles, attached to bones or internal organs and blood vessels, are responsible for movement. Nearly all movement in the body is the result of muscle contraction.
Explanation:
A man is 100,000 times larger in micrometers than the amoeba, since 17 micrometers is 0.000017 meters, and 1.7 meters is 1,700,000 micrometers
