It's because proteins are very small and hard to see.
Answer:

Explanation:
The first step is:

Second step is:

Multiplying second step by 2, and adding both the steps, we get that:

Cancelling common species, we get that:

Answer:
To find the average atomic mass, you take a certain number of atoms, find the total mass of each isotope, and then divide the total mass of all the atoms by the total number of atoms. Assume that you have, say, 10 000 atoms of carbon
Explanation:
The answers are:
1. D
2. B if it is a check all that are true it is b & d