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".
Answer:
Option C
Explanation:
There are cases when two organism of different species mate to produce offspring but that offspring is unable to reproduce further. Hence, such organisms do not belong to the same species. Thus, Option D is incorrect
However, when two organisms are able to reproduce viable offspring, they are said to be of the same species. Such organisms are also similar in looks.
Hence, option C is correct
Answer:
what is thought to be the main driving force behind plate movements
A.) Through metabolic processes.
