Answer:
In this case the mass number would be 11.
Explanation:
The mass number of an element is the sum of the protons and neutrons. The number of neutrons for a given element is the only number that can change and still have the identity of the element stay the same, (because the atomic number is the number of protons).
After your first exposure to a pathogen, you have memory T cells that will remember the antigen of the pathogen son in the future if you would come in contact with the same pathogen your body will recognize it right away and be able to kill it much faster
