The ozone layer helps prevent harmful UV rays from entering the atmosphere.
Mercury has the smallest orbit and neptune has the largest. so neptune would take a longer amount of time to orbit the sun.
Answer:
A
Explanation:
Passive transport does not require energy. The substances follow the concentration gradient, meaning they go from high to low. Active transport goes against the concentration gradient. Substances go from low to high, so it requires energy.
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</span>Most cells of the body have self markers on the surface of their cell called the major histocompatibility complex (MHC). The MHC allows cells of the immune system to recognize the cell as part of our self.<span>system to recognize the cell as part of ourself.</span>
