Answer:
Chemical reactions make and break the chemical bonds between molecules, resulting in new materials as the products of the chemical reaction.
Explanation:
Breaking chemical bonds absorbs energy, while making new bonds releases energy, with the overall chemical reaction being endothermic or exothermic.
4 Co(s) + 3 O2(g) = 2 Co2O3(s)
I guess covalent bond is formed
The answer is mitochondria.