Answer:A weak immune system
Explanation:
When people get older their immune system becomes weak including the function of the T cells which are cells responsible for fighting infections.
This means it becomes hard to recover from a flue when someone get sick and they are always prone to sickness since their immune system no longer has the power to fight infections.
25.
26.
27. chemical bond
28.compound
29.Mixture
30.Molecule
The answer would be B The social imperative
