Infrared rays are felt <span>as heat is transferred between Earth and the atmosphere</span>
Are you sure these are the only answer choices? I believe the answer would be Hippocampus, but it's not up there.
Answer:
Example of natural active immunity is fighting off cold and artifical active immunity is building up a resistance to a disease due to immunization and allergic reaction is an response to antigen resulting from active immunity
By the late 1830s, botanist Matthias Schleiden and zoologist Theodor Schwann were studying tissues and proposed the unified cell theory. The unified cell theory states that: all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells.