Give any four factors necessary for a healthy person.

(N/A) For a person to remain healthy,the following four factors are essential:
$(i)$ Clean surrounding environment: $A$ clean environment prevents the spread of air-borne and water-borne diseases.
$(ii)$ Personal hygiene: Maintaining cleanliness of the body helps in preventing infectious diseases.
$(iii)$ Proper and balanced nutrition: Sufficient and nutritious food is necessary to strengthen the immune system of the body.
$(iv)$ Immunization: Timely vaccination against severe diseases provides protection and prevents illness.