*Sigh* It's important because conserving energy helps the environment and lets you have a little more pocket money when the bills come around.
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>
Answer:
true ameoba is unicellular
Where is the phot for the video?
It's called Data
hope it helped give thanks :)