Which of the following diseases is caused due to an allergic reaction?

Allergy is caused by the release of chemicals $Q$ from $P$. Identify $P$ and $Q$.

Agents which produce allergy are known as:

$Hay \, fever$ is a type of which disease?

Which of the following secretions from mast cells induces an acute response in an allergy?

$A$ person shows symptoms like sneezing,watery eyes,running nose,and difficulty in breathing upon exposure to certain substances in the air. Which type of antibody is produced during such a condition?