Question

correct the sentences by placing apt word instead of the brakated one
a, (right atrium) is the double layared protective covering of heart
b, valves are seen imside the (capillary)​

Answer 1

Answer: a) pericardium

               b)  veins

Explanation: Pericardium is is the double layared protective covering of heart, the space between these two layers are known as pericardial cavity and this cavity are filled with a fluid  which protects the heart from shock.

Valves are seen inside the veins because they ensure the blood flow only in one direction. But artery donot require valves bceause pressure is very strong from heart that blood can flow only in direction.