Against which of the following does interferon act?

In higher vertebrates, the immune system can distinguish between self and non-self cells. Due to genetic or other unknown reasons, the immune system sometimes loses this property and starts attacking self-cells, resulting in:

Which of the following immune responses is responsible for the rejection of a kidney graft?

Which of the following cells are not considered phagocytic cells?

Given below are two statements.
Statement $I$: Passive immunity is acquired when readymade antibodies are received by body cells.
Statement $II$: Resistance induced by $BCG$ vaccine is an example of passive immunity.
In the light of the above two statements,choose the correct answer from the options given below.

Many microbial pathogens enter the gut of humans along with food. What are the preventive barriers to protect the body from such pathogens? What type of immunity do you observe in this case?