Three variables can be used .
1. Sun 2. Moon 3. Earth
These are suggestions that lizzie can control:
1.<span> Discover how long the Earth takes to orbit the Sun
2. how many hours it takes the Earth to spin around once on its own axis, 3. how long the Moon takes to orbit the Earth</span>
The inferior vena cava brings deoxygenated blood back into the heart from the lower body. For comparison, the part that directs deoxygenated blood from the upper body is the superior vena cava.
The statement is true that T-cells are a type of immune cell system that recognizes pathogens in the body.
T-cells are the lymphocytes that are involved in providing acquired immunity to the body. They can recognize the pathogens presented by the antigen presenting cells. There are two types of t cells: helper T cells and Cytotoxic T cells.
Immune cells are the cells of the immune system that are involved in protecting the body from infection, allergies and foreign pathogens. There are several immune cells that perform several functions. The example of such cells are: phagocytes, lymphocytes, dendritic cells, etc.
To know more about T cells, here
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