Insects may be preserved in the hardened sap of trees called?

Amber, is your answer.

Amber is made from hardened sap of trees, and preserves whatever falls inside.

hope this helps

~Audiomachine

Hardened tree sap is called amber.

Sometimes, isects get caught on this sap, and when it hardens, it remains with the insect inside of it, as if it were a fossil.

→ The image below shows a mosquito that was found inside a piece of amber.

Hope it helped,

BioTeacher101

a. by using fur or clothes to trap heat energy near the body