Sulpha drugs are used for

Match List-$I$ with List-$II$.

List-$I$ (Drug class)	List-$II$ (Drug molecule)
$(a)$ Antacids	$(i)$ Salvarsan
$(b)$ Antihistamines	$(ii)$ Morphine
$(c)$ Analgesics	$(iii)$ Cimetidine
$(d)$ Antimicrobials	$(iv)$ Seldane

Choose the correct answer from the options given below:

$A$ large number of antibiotics have been isolated from:

Which of the following statements are correct?
$(i)$ Drugs that mimic natural messenger by switching on the receptor are called agonists.
$(ii)$ Shape of the receptor does not change after attachment of chemical messenger.
$(iii)$ $A$ cationic detergent is formed when stearic acid reacts with polyethylene glycol.
$(iv)$ Seldane is an antihistamine.

Which of the following sweeteners is limited to use in soft drinks?

Sleeping pills are recommended by doctors to patients suffering from sleeplessness,but it is not advisable to take their doses without consultation with a doctor. Why?