To trace our maternal lineage, we observe mutations that have accumulated in our mitochondrial dna (mtdna). in the dna isolation and amplification lab, we amplified a highly variable and non-coding region in the hyper-variable segment i of our own mtdna using polymerase chain reaction. why did we choose to amplify a non-coding region rather than a coding region to determine our lineage?

In the coding region, natural selection tends to eliminate all of the mutations because of the high importance these regions have. The coding region contains genes that synthesize proteins and the changes in the DNA sequence can have devastating effects on the cell. Therefore, there are very few differences in the sequences of coding regions that can help us trace the lineage.
On the other hand, in the non-coding regions, the mutations often accumulate because they have little effect on the cell and the adaptive value of the organism. This enables us to trace up the lineage by comparing the sequences and seeing the differences in the sequences. 

Need the answers if its a multiple choice question

It depends on the surface of the levels. the rougher the surface, the greater is the frictional force. for rougher surfaces, you would need to exert greater force to move the object. the concept is that, you must overcome the frictional force in order to bring the object into motion. this is the reason why we add lubricants to the joints so they could easily move. this answer was on