The best sample is one that is a systematic sample.

a. convenient.
b. representative of the population.
c. purposefully selected.
d. none of the above.

b.representative of the population.  

Explanation:

           A sample is a collection of small quantity or part which is normally taken from a large mass of quantity that represents the whole having the same characteristics.

          A sample should be a representative of the entire population in consideration to make sure to generalize the results from the sample of the research to the population as a whole. A sample is a subset of the population and is considered as the best sample when it represents the whole population.

Hence the correct option is (b).

answer; cultural trait;

answer; the smaller of the two reciprocal products of translocated chromosomes is lost; after several cell divisions, only the larger of the two translocated chromosomes remains,its reciprocal is lost;