Which of the following is associated with the discovery of the well-known fungicide Bordeaux mixture?

The chemotherapeutic substance derived from a living organism that has an inhibitory effect on a parasitic organism is known as:

The oral vaccine for polio was discovered by:

Vaccines are prepared from which of the following?

Select the correct option to fill up the blanks.
$(i)$ Diseases which are easily transmitted from one person to another,are called $.....$ diseases.
$(ii)$ In human body,parasite of malaria initially multiplies within the $........$ and then attack the $......$
$(iii) ......$ is the yellowish fluid secreted by mother during the initial days of lactation.
$(iv) ......$ and $.......$ are the primary lymphoid organs.

$A$: It is considered advantageous to give the polio vaccine orally.
$R$: It prevents reinfection by causing intestinal immunity.