What is the difference between a virus and a bacteria?

Priya's mother uses iodised salt at home. One day while cooking,Priya asked her mother about iodised salt. She said people who do not use iodised salt suffer from deficiency of iodine which leads to goitre and hypothyroidism.
$(a)$ What are the physical symptoms of goitre and hypothyroidism?
$(b)$ How will you inform others about the importance of iodised salt?
$(c)$ Is iodine a metal or a non-metal?
$(d)$ What are the physical properties of iodine?
$(e)$ What is the difference between iodised salt and normal salt?

State whether the following statement is true or false:
Social equality and harmony are necessary for individual health.

What causes encephalitis? How does it enter the body? Which organ does it infect? What are the symptoms if this organ is infected? How can it be prevented?

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	$(c)$

$(a)$ State the method of transmission of each of the following diseases:
$(i)$ Cholera
$(ii)$ $AIDS$
$(iii)$ Malaria
$(iv)$ Pneumonia
$(b)$ Name the disease a person will get if the pathogen targets the liver of a person.