Which of the following is a relatively new disease?
a. small pox
b. bird flu
c. tuberculosis
d. polio

Option B

Explanation:

Small pox disease was discovered Edward Jenner in 1796. The disease causing agent of Tuberculosis i.e bacteria Mycobacterium tuberculosis was however discovered in March 1882 by Dr. Robert Koch

The first interaction of HPAI A(H5N1) virus  with human was reported in year 1997 in Hong kong.

And first case of polio was reproted in  Vermont in U.S. in 1894

hence, among all the bird flu is the most recent disease

Option B is correct

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.  

not always but somethings can be reproduced in a laboratory.