Credibility is essentially the believability of the study, and it is determined by both the trustworthiness and expertise of the researcher. Recently, concerns have arisen over Nalgene drinking bottles and the chemicals they may be releasing into the water. Two scientists publish their findings. One who works for a major Nalgene producing company, the other does not. Which scientist is more credible?

The scientist who has no conflict of interest is, in principle, more reliable  

Explanation:

All scientific publications must include a Declaration of Interest (also known as Disclosure Statement) by which authors state that there's no personal or financial interest that might be affecting the objectivity of their investigations, results and conclusions. If no conflict exists, the author should indicate that "there is no conflict of interest". In this case, the scientist who works for a Nalgene producing company should state that it is a potential conflict of interest.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).

producers: apple trees, potatoes, carrots, grains, acorns, cabbage, grass, corn, lettuce

consumers: deer, mice, rabbits, chickens, squirrels, horses, worms, cows

predators: eagles, frogs, wolves, owls