A. <span>Exposure to an antigen
Exposure to viruses and antigens led to the foundation of modern vaccination. Vaccination introduces an antigenic material that helps the ability of the immune system to adapt a specific pathogen, therefore leading to a long-term immunity.</span>
<span>photometric images, light curves, and spectra</span>
True
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Answer:
A. intrusive igneous rock
Explanation:
I believe that the answer is genotype
