Riddle

I am very important to all living creatures. I was firstborn in the sun. I am a chapter in textbooks and I am not made of fire. I make the sun-worthy. Too much of me may kill you. But humans can still prevent me. What am I?

Choose an answer

A.Light
B.Energy
C.Radiation
D.Heat!
Hint: It's a word with 4 letters, starting with "H".

Answer

Heat!

Why this is the answer

Heat originates from the sun, is studied in science textbooks, and can be deadly in excess yet is manageable by humans.

This riddle is filed under How, What, Why Riddles and rated Hard.