Allergic reactions are most closely associated with

Immune response to usually harmless substances

Explanation:

Allergic reactions occur when the immune system has a response against a substance that it considers to be dangerous and it releases antibodies which causes different reactions in the body that produces symptoms like sneezing, cough and red eyes. According to this, the answer is that allergic reactions are most closely associated with immune response to usually harmless substances.

the eggs of the insects should be the first thing collected at the scene.

false

there really is life in the deepest part