The diseases which occur at irregular intervals and locations are known as

Which of the following is an auto-immune disease that affects many people in our society?

Which substance,when present in higher amounts in the body,leads to a fever-like condition?

Which is the primary physical barrier in our body?

What is $PMNL$?

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.