During an allergic reaction, the binding of antigens to IgE antibodies initiates a response, in which chemicals cause the dilation of blood vessels and a host of other physiological changes. Such chemicals are

‘Bacillary dysentery' is caused by

Humoral immunity is due to

Which one of the following depresses brain activity and produces feelings of calmness, relaxation and drowsiness

What is the main cause of concern for today's youth ?

Drugs, shocks and psychotherapy are the treatments of