Answer:
A hydrogen atom is an atom of the chemical element hydrogen.Carbon is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds.
In chemistry, an element is a pure substance consisting only of atoms that all have the same numbers of protons in their atomic nuclei.
Explanation:
The answer to your question 12
Answer:
compound can be broken down into smaller compound or their basic element by chemical change
Overproduction of offspring, inherited variation, and the struggle to survive.
So: b, d, and e