Answer:
Cetacean
Explanation:
Let us start with the family Delphinade which is the largest in the Cetacean order, and relatively recent: dolphins evolved about ten million years ago, during the Miocene. Dolphins are among the most intelligent animals and their often-friendly appearance and seemingly playful attitude have made them popular in past and current human culture.
Answer:
Pericardial sac has protective tole
Explanation:
Pericardial sac or pericardium is a fibrous tissue that surrounds the heart. It has two coats:
- the outter coat-parietal pericardium
- the inner coat-visceral pericardium or epicardium which is double-layered and contains pericardial fluid between those two layers (pericardial fluid is necessary as a lubricant for the heart movement).
Besides lubrication, percardium also protects heart from infections, fixes it and limits its movements.
Answer: When the ball reaches the highest point and stops briefly.
Explanation: All thrown projectiles make a parabola, the peak of the parabola will have the greatest gravitational potential energy.
The aortic valve prevents backward flow of blood into the left ventricle.