The best answer for the blood vessels' valves would be these are veins that would then help in preventing the back flow of blood because the walls have small muscle to pump the blood back to the heart.Hope this is the answer.
Answer:
A. Vena cava
Explanation:
The aorta can't be the answer because it is the largest artery in the human body and it carries oxygenated blood. The pulmonary artery carries deoxygenated blood into the lungs for oxygenation. The pulmonary veins transfer oxygenated blood from the lungs to the heart. And lastly, the vena cava is the right answer and it returns deoxygenated blood back into the heart.
Answer:
"Extrinsic factors that can cause esophageal blockage include compression of the neck and lesions in the central nervous system that affects the muscles in the esophageal wall. The following are some of the common causes of esophageal blockage. Obstruction due to foreign object or food. Food and foreign objects can cause a blockage of the esophageal lumen."
Answer:
B
Explanation:
Countries like China, USA, and India have some of the highest cardiac disease rates. All of these countries are developed or industrialized.
Hope this helped.
Answer:
B
Explanation:
Because from other people they would tell you Their most productive time of day. news and internet would just tell you what some scientific study said. brainliest if im right :) good luck
