Which best describes why gel electrophoresis works?
a. dna with mutations cannot pass through the gel.
b. dna with a more negative charge moves more slowly.
c. smaller dna segments move more easily through the gel.
d. reverse transcriptase molecules have a negative charge.

Ans. (C). smaller DNA segments move more easily through the gel.

Gel electrophoresis is defined as a molecular biology technique, used for the separation of DNA molecules from a mixture. In this,  the agarose gel, placed in a buffer, is used through which, molecules of DNA get separated.

The gel electrophoresis equipment has two poles, positive pole and negative pole at the each end. When current is allowed to the system, DNA molecules (negatively charged) run on the gel (towards the positive charge) according to their shape and size.

The smaller DNA fragments move faster and more quickly than larger fragments, and bands of different DNA molecules are formed in the gel according to their size.

Thus, the correct answer is option (C).

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."

oxygen +1 most likely