The body uses non-specific immune responses as the first line of defense when we are exposed to pathogenic or disease causing organisms. Which of the following factors is a nonspecific response?

A. Antibodies are produced after an infection.

B. Bacterial cell surface proteins start a response.

C. Unbroken skin provides a physical barrier.

D. Vaccine injections will imitate viral exposure.

C

Explanation:

A nonspecific response is a defense you are born with. You were born with unbroken skin to be a physical barrier.

d.

explanation:

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.