Question

Old persons are usually less immune to pathogenic organisms. This decrease in immunity is due to _____
a) Thymus
b) thyroid
c) parathyroid
d) pineal​

Answer 1

option (a) thymus is correct option

Explanation:

Thymus plays a major role in the development of the immune system. This gland secretes the peptide hormones called thymosins. Thymosins play a major role in the differentiation of T-lymphocytes, which provide cell-mediated immunity. In addition, thymosins also promote production of antibodies to provide humoral immunity. Thymus is degenerated in old individuals resulting in a decreased production of thymosins. As a result, the immune response of old persons become weak

Answer 2

a) thymus ( first of all check)

Explanation:

I am not sure