One way to get consistent, valid data is to be sure that instruments are calibrated properly.
use simple instruments to make measurements.
select the best data to place into data tables.
make the measurements as quickly as possible.

the answer to your question is b

the correct answer is:

a population changes in response to a change in the environment.

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.