Cells need a source of energy, they get this energy by breaking down food molecules to release, the stored chemical energy.
Answer: The base pairing in the DNA molecule is incorrect.
This is because adenine (A) always pairs with thymine (T) and guanine (G) always pairs with cytosine (C).
1. 25% which is bb
2. All living things are made of cells
3. Grams, mass
Hope that helps.