Assertion `:-` Platelets repair dammaged endothelium of blood vessels.
Reason `:` Platelets secrete serotonin which is a vaso constrictor

Assertion (A): Alveoli contain an extensive network of blood vessels. Reason (R): Alveoli is the site where exchange of gases occurs.

Assertion : Pituitary gland is also called master gland. Reason : It secretes a number of trophic hormones which regulate secretion from other endocrine glands.

Assertion :- Smallest blood cell is RBC Reason :- Platelets are cell fragments not true cells.

Assertion : Heparin is a natural anticogulantt indside the blood vessels . Reason : It is example of homopolysaccharide .

Assertion : Heparin is a natural anticogulantt indside the blood vessels . Reason : It is example of homopolysaccharide .

Assertion (A) : Our body maintains blood sugar level. Reason (R) : Pancreas secretes insulin which helps to regulate blood sugar levels in the body.

Assertion: Blood coagulates in unijured blood vassels. Reason: Uninjured blood vessels release an anticoagulant heparin.

Assertion. Corpus luteum is produced by Graafian follicle after ovulation Reason. It secretes estrogen which is necessory to maintain pregnancy.

Assertion: Blood does not coagulate in unijured blood vessels. Reason: Uninjured blood vessels release an anticoagulant heparin.