During old age ,the immunity of a person begins to decrease and as a result , the they become more susceptible to infections and diseases . What could be the probable reason for this ?

old people have weak immune system. What could be the reason?

Old people have weak immune system. What could be the reasons?

Old people have weak immune system. What could be the reasons?

Menstrual cramp is a common problem that occurs during the beginning of menstrual period. What could be the reason for this?

Read the given passage and answer the question. Sukriti and Priya are good friends and study in I standard of a reputed school. On a hot summer day, while they both were playing in the school playground, Priya felt uncomfortable and sat down. After some time she developed acute headache and high fever. Her legs stopped moving and she also felt some stiffness in her neck. Soon she became unconscious. What could be the probable reason for Sukriti not being affected by pathogen of this disease?