A closed system is a system that makes no physical or chemical exchanges with its environment. Of these systems provided as choices (tree, human, clock, car), only a clock does not make exchanges with the environment, except for energy.
Therefore, of that list, only a clock would be a closed system.
Hope that helped! =)
Answer:
Melanin helps the mouse survive because of the fur color. Its color helps it to blend into its surroundings, making it a lot harder for predators to kill it, as the predators have a harder time seeing the mouse.
Explanation:
<span>Glucose is the human body's key source of energy as it provides energy to all the cells in our body. Glucose also is critical in the production of proteins, lipid metabolism and is a precursor for vitamin C production.</span><span><span>Glucose is the sole source of fuel to create energy for all brain and red blood cells.</span> The availability of glucose influences many psychological processes. When glucose levels are low, psychological processes requiring mental effort l(self-control, critical thinking and decision-making) become impaired.
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Answer:
approximately 4.5 billion years ago
Explanation:
Populations tend to grow because of repopulation.
