The aortic valve is the final door blood goes through as it exits the heart. Obstruction of that valve is called stenosis and leakage of the valve as it closes after each heartbeat is called regurgitation
<span>The element Carbon is the </span>building block for all<span> known living things. That is why, in some science-fiction movies you hear the term, Carbon-based units.</span>
Answer:
it was only 90 percent effective
Explanation:
In 1954 a massive controlled field trial was launched, sponsored by the National Foundation for Infantile Paralysis. Almost two million U.S. children between the ages of six and nine participated. In some areas of the country half of these “Polio Pioneers” received the vaccine, while half received a placebo. In other areas of the country children who did not receive any vaccine were carefully observed. On April 12, 1955, Thomas Francis, Salk’s mentor and the director of the trial, reported that the vaccine was safe, potent, and 90% effective in protecting against paralytic poliomyelitis.
Answer:
Many common products, such as wooden furniture, paper, and books, are made from trees. This act of human being causes the destruction of habitats. Explanation: The term trees, forest, plants etc are used to denote those living organism which follows living mechanism which states that live and let live
Explanation:
