Answer:
This question is incomplete, the options are:
A) Decreased temperature
B) Strong southerly winds
C) Presence of a predator
D) Lack of water
The answer is C
Explanation:
A stimulus is something that provokes a response or reaction in a living organism. It can either be internal or external. An animal can respond to stimulus such as hunger, heat, predator etc.
However, among all the listed stimuli in the options, the PRESENCE OF A PREDATOR is most likely to result in a more rapid heartbeat in an animal. This is because the predator stimulus will require the animal to respond by running in order to survive. Running will increase its metabolic activity and cause its heartbeat to increase.
The answer is (B. Medium) because it has to travel through the ear drum evenly without busting it. Hope this helped :)
Answer:
The correct answer would be Atria push blood into the ventricles and Ventricles push blood out of the heart.
In humans, four chambered heart is present with two atria and two ventricles.
Deoxygenated blood from all over the body is passed into the right atrium through vena cava (superior and inferior).
Simultaneously, oxygenated blood from the lungs is passed into the left atrium of the heart with the help of pulmonary vein.
Both the atria contract at the same time to drain their blood into respective ventricles.
The ventricles undergo relaxation while receiving blood.
The valves present between the atria and ventricles (tricuspid and bicuspid valve) ensures that the blood flows in one way direction only. They shut down as the ventricles contract and produce the sound "lub".
The ventricles contract simultaneously to pump blood out of the heart. The right ventricle pumps deoxygenated blood into pulmonary artery which takes the blood to the lungs for oxygenation.
The left ventricle passes the oxygenated blood through aorta to all the parts of the body.
The pulmonary and aortic valves prevent the back flow of blood and shut at the same time which creates second sound called as "dub".
