Neurotransmitters, such as acetylcholine--the major neurotransmitter found in the human body, act over a short time and they are quickly removed from the synapse by enzymes (i.e. acetylcholinesterase which breaks down acetylcholine to acetyl-CoA and choline).
4.6 million years ago the earth had less green house gasses so the atmosphere was cooler rather than hotter.
<span>Secondary succession is faster than primary succession because the soil is already there and the soil usually contains many seeds.</span>
Black hole
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