People who have darker skin have more melanin which is a black or dark brown pigment in the skin. When we are out in the sun our skin produces more melanin, which helps our skin be more resistant in the sun. This is why we tan.
Answer: ok ill help:
1. over population happens when too many babies are born and the place gets crowded
2. same thing happens is too many immigrants go to 1 place E.G UK
Nitrogen-fixing bacteria change nitrogen into a form of soluble nitrates that plants can use ...the air is 80% nitrogen but it is in N2 form which plants cannot use
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The glucose and the oxygen travel out into the body through the circulatory system to reach cells that need energy. The cells use the glucose and oxygen from the circulatory system for energy production.
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Trees share water and nutrients through the networks, and also use them to communicate. They send distress signals about drought and disease, for example, or insect attacks, and other trees alter their behavior when they receive these messages.
