What is important to keep in mind when selecting a sample? a. The sample should be chosen based on specific criteria, such as the youngest students in the
class.
b. The sample should be chosen at random so that it is fair.
c. The sample should consist of every person in the population being studied.
d. The sample size should always be exactly one person or piece of data.

b. The sample should be chosen at random so that it is fair.

Step-by-step explanation:

Looking at the options:

a. The sample should be chosen based on specific criteria, such as the youngest students in the  class.

This is false. Choosing a sample size based on specific criteria may skew the data unfairly. For example, in a survey on students' studying habits, choosing only the students with lowest grades would be an inaccurate representation of the data.

b. The sample should be chosen at random so that it is fair.

This is true. Randomizing a sample eliminates any bias, whether intended or unintended.

c. The sample should consist of every person in the population being studied.

Although it is ideal to survey every person in order to get the most accurate data, doing so is often impossible given the scope of a data set. Doing a survey on high schooler's study habits cannot possibly get data from every person in the population, as there are high school students across the world.

d. The sample size should always be exactly one person or piece of data.

One person's data is not a survey, it is just an opinionated study. Sample size should always be large enough to eliminate any accidental bias.

The correct choice is B.

homozygous. one is homozygous, while two is heterozygous.