Physical variation can be expressed with physical characteristics such as hair color, eye color, pigmentation, etc.
Mitochondrial and chloroplasts
letter A..
Rivers with regularly floods leaves fertile soil along their banks which is why a civilization will choose to live near there.
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What is Fertile?</h3>
This is defined as the ability of land to produce crops and vegetation in abundant quantities.
Flooding washes minerals and humus to the bank of rivers which favors growth of plants which is why option D was chosen.
Read more about Flooding here brainly.com/question/134213
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