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Dafna11 [192]
3 years ago
6

Although earth is estimated to be 4.5 billion years old, and although life first appeared about 4 billion years ago, plants did

not appear until about _______ years ago.
Biology
1 answer:
timurjin [86]3 years ago
3 0
470 million years ago
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Answer:

B) Na+

Explanation: Na+ molecule is polar, oxygen and carbon dioxide are nonpolar molecules. The cell membrane is a <em>phospholipid bilayer</em> made up of lipid molecules with polar and nonpolar ends. Since it is a bilayer, two phospholipid layers are arranged, one on the other in such a way that one faces the back of the other. The non polar ends are away from outside and inside of the cell, while  the polar ends faces towards all the molecules inside and outside the cell.

Since polar-polar molecules repel each other, Na+ can't pass through the cell membrane easily. So it uses the proteins attached the cell membrane inside and outside to transport such molecules by using energy in terms of ATP.

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ubiquitin targets CDKs

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Waves interact with matter in several ways. The interactions occur when waves pass from one medium to another. Besides bouncing back like an echo, waves may bend or spread out when they strike a new medium. These three ways that waves may interact with matter are called reflection, refraction, and diffraction.

Explanation:

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No, it has too many variables or possible changes.

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