Answer:
can you upload the question again..coz some part are not showing
Answer:
Over our lifetime, our DNA can undergo changes or mutations that result in differences in the DNA sequence and may affect the proteins that are made. Mutations can occur as a natural consequence of errors in DNA replication or as a result of exposure to environmental factors such as smoking, sunlight or radiation.
Explanation:
The number of protons and elctrons adds up to the mass number
The energy needed by a system to initiate a process is called as the activation energy. It describes the minimum energy which must be available to a chemical system with potential reactants to result in a chemical reaction. Hope this answers the question.