Answer:
a. antigen
Explanation:
The Immune system is composed of immune cells that defend the body against foreign substances such as bacteria or virus. Lymphocytes (B and T cells) are one of the main immune cells
Lymphocytes have the ability to recognize and bind to antigens, wich are substances foreign to the body ( i.e bacterial or virus elements) that evokes an immune response.
I believe it is oxygen and carbon dioxide
Answer:
It is often assumed that the moon is a perfect sphere, which it is not. The side of the moon facing earth is more dense than the side facing away. Therefore, it takes energy for the moon to rotate its earth-facing side away from the earth. Such energy is not currently available, so the same side always faces earth, caught in earth’s gravity.
Explanation:
Hope this helps you a lot my boo!