The phospholipid bilayer is a universal component of all cell membranes. Each phospholipid molecule has a hydrophobic(water repelling) and a hydrophilic( attracted to water) end. This allows the phospholipids to arrange themselves in a way that makes a cell membrane not able to dissolve in water. The bilayer is also semi-permeable which allows only certain molecules to enter the cell.
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Answer:
The genetic variations that are best suited for their enviornment
Explanation:
Those that are not well suited for their environment will die off, leaving only the ones that are suited for it. This species will slowly take hold until the species has adapted and become a completely different one.
The answer is <span>neurohormones; releasing; inhibiting</span>
A frog's lungs don't work that well, but since it's skin is so thin, oxygen and carbon dioxide can pass trough it.