<span>The answer is valves. One </span><span>feature that the entrances and exits to the heart need in order to maintain this flow pattern is the valves. E</span><span>ntrances and exits to the heart may need valves in order to maintain this flow pattern. There are valves that control blood flow to the ventricles, and valves that control blood flow out of the ventricles.</span>
Answer:
El umbral de audición es la intensidad mínima de sonido capaz de impresionar el oído humano. Aunque no siempre este umbral sea el mismo para todas las frecuencias que es capaz de percibir el oído humano, es el nivel mínimo de un sonido para que logre ser percibido.
Explanation:
The answer is Sperm and egg
Prey-predator relationship. Explanation: The relationship between the praying mantis feeding on a bee.
