Question

Exists throughout Earth's crust. It is the building block of all living things.​

Answer 1

Answer: Carbon

Step-by-step explanation:

Carbon is considered to be the building block of all living things as it is very important in the formation of compounds that are needed by living things to survive such as Carbohydrates and Protein and many more.

This is down to its ability to form stable compounds with other elements such as Hydrogen and oxygen both of which are present in Carbohydrates and Proteins.

Carbon exists in the Earth's crust as Carbonates in water, rocks, petroleum and living things as well especially plants and trees which release a significant amount if they are cut down.