The right answer is vein (it contains blood and has valves).
The infra-cardiac veins of small and medium caliber possess this system of fight against gravity. The valves consist of a dense connective tissue, surmounted by endothelial cells, corresponding to a fold of the intima. They allow blood circulation in the sense organ / heart but prevent venous reflux.
<span>The correct answer is C. The Golgi apparatus. This is the packaging center of the cell. It is responsible for receiving cell products and transporting them within vesicles either within the cell or to surrounding cells. Lysosomes are the trash collectors of the cell, responsible for processing wiaste. The cell membrane makes up the cell's enclosure and selectively allows material into and out of the cell. The endoplasmic reticulum contains ribosomes and is responsible for assisting in protein production.</span>
<span>The exosphere is the fifth and final layer of the atmosphere. This layer is a little thicker than the theremosphere at 500-1000 km thick.</span>
D. In a structure of the female reproductive system.
