The answer is D) a neutron.
When we say an atom's mass is, like 5 atomic mass units actually we are saying that the total number of the neutrons and protons in its nucleus is 5.
The mass of a neutron and a proton is each one atomic mass unit.
Mass of a neutron is approximately 1 atomic mass unit.
1. C
2. E
3. A
4. B
5. D
I hope that helps <3
Answer: The person lived for 80.66 years.
Explanation:
Heart beat of the person = 73 beat /min
Number of total heart beats = 
Life span of the person : 
1 year =525600 mins
Life span = 
The person lived for 80.66 years.