Name two types of diseases caused by regularly breathing in the polluted air.

You are aware of the $Polio$ $Eradication$ $Programme$ in your city. Children are vaccinated because:

Why is the immune system essential for our health?

Name diseases which are caused by:
$(i)$ virus
$(ii)$ bacteria
$(iii)$ protozoa.
(Give two examples for each)

Study the given chart carefully and fill in the blanks $(a)$,$(b)$,and $(c)$:

$S$.No.	Name of the disease	Causative organism	Mode of transmission
$1$. Polio	$(a)$	Infection of virus directly/orally
$2$. $(b)$	Lyssa virus	Virus enters human body with saliva of an infected animal
$3$. Typhoid	Salmonella typhi	$(c)$

Fill in the blanks:
$(a)$ Pneumonia is an example of . . . . . . disease.
$(b)$ Many skin diseases are caused by . . . . . . .
$(c)$ Antibiotics commonly block biochemical pathways important for the growth of . . . . . . .
$(d)$ Living organisms carrying the infecting agents from one person to another are called . . . . . . .