Respuesta :

Viruses because children immune system cannot repeal parasites (no one can) or bacteria that is why we wash or hands. Fungi is not something we can repeal either.

Answer:A - viruses

Explanation:

Children immune system is comparitively weeker than the adult immune system.

Thus children are more susceptible to acquire viral infection which exhibit a parasitic prolonged infection. Children are more susceptible to cold and flue virus than adults due to lack of immunity.