So we know that to transport materials in or out of the cell, we need to have access to both the inside and outside of the cell. This would require that the protein be a transmembrane protein that reaches both the inside and the outside of the cell.
So in this case, let's look at pore proteins. These are proteins that cross a membrane and act as a pore for the materials that need to cross the membrane.
One example of a pore protein is an aquaporin. These proteins aid in the transport of water into or out of a cell.
Therefore, the answer to your question is: A) Pore proteins.
 
        
             
        
        
        
Answer: <u>Guanine
</u>
According to Chargaff's rule, the base pairing in the DNA and RNA is fixed. Adenine always pairs with Thymine in DNA and Uracil in RNA. Guanine pairs up with cytosine. This complementary base pairing is universal and constant. That's why amounts are also equal. It means if cytosine is 20% in any DNA sample, then amount of guanine would be 20% as well. 
 
        
             
        
        
        
Python shell.
Hope this helps!
-Payshence xoxo<span>
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If I am not wrong the most important ones are: 
1.Sacrum, 
2.coccyx, 
3.cranium, 
4.sternum, 
5.ribs, 
6.clavicle, 
7.pelvic girdle, 
8.patella, 
9.mandible, 
10.tibia, 
11.fibula, 
12.carpals, 
13.tarsals, 
14.metatarsals, 
15.metacarpals, 
16.costal cartilages 
17. Cervical vertebrae