The study pushes back the clock on the origin of Earth's water by hundreds of millions of years, to around 4.6 billion years ago, when all the worlds of the inner solar system were still forming. Scientists had suspected that our planet formed dry, with high-energy impacts creating a molten surface on the infant Earth.
Answer: 4.6 billion years.
Answer:
The correct answer will be option-C
Explanation:
Mammals are warm-blooded animals that are they need to maintain the internal temperature irrespective of the external temperature at a constant rate or 37° C.
In cold conditions the person exposing the body parts to cold conditions response either by producing heat or conserving the heat in the body.
If a person removes the gloves, then a physiological change leads to the change in the diameter of the blood vessels. The diameter of the blood vessels reduces which reduces the loss of heat from the body as constriction of the blood vessels decreases the surface area to be exposed to cold conditions.
Thus, Option-C is the correct answer.
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".
GG, because both parents have the exact same gene which would cause the offspring to have the same gene.
