The mismatch repair system recognizes mismatched base pairs, removes a portion of the dna strand containing the error, and then resynthesizes the missing dna using the correct sequence as a template. but what if the mismatch repair system instead removed a piece of the dna strand that contained the correct sequence? what would replication of this improperly repaired sequence produce?

It could lead to several later problems in the cell.

Explanation:

Removing a piece of DNA could severely affect the cell but it could also cause nothing. Depending on the part that is damaged, it could codify for a vital protein but it could also be an intron, which are pieces of DNA that don't codify for any protein. This has been recently researched and even though there are introns that could cause some serious trouble, most of them are an unknown matter to nowadays scientists. Anyway, a wrongly repaired sequence could end in a mutation that can potentially damage the cell and therefore the organism.

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well, i believe that the answer is 2. : 3