Elderly people are more prone to get respiratory infection because of
1. Decline in cell mediated immunity
2. Decline in humoral immunity
3. Decreased formation of secretory IgA
4. Fewer or less functional cilia
Select the correct answer using the code given below:
1
1 and 2 only
2
1 and 4 only
3
1, 2 and 3 only
4
1, 2, 3 and 4