Ascientist wants to know if consuming fast food increases obesity in teens. he interviews 500 nutritionists, and 450 of them believe fast food consumed more than once a week increases obesity. the scientist concludes that consumption of fast food increases obesity. why is the scientist's conclusion most likely unreliable?
the data about the nutrition of fast food is inaccurate.
the results of the investigation cannot be repeated.
the survey introduced biased information.
very few people were interviewed.

The data about the nutrition of fast food is inaccurate.

Explanation:

Although the scientist has the report of many professionals about the influence of fast foods on obesity, the data on these foods in this research are inaccurate for the scientist to be able to draw a conclusion. This is because the scientist does not demonstrate what factors make eating through fast foods influence obesity, the scientist does not show the composition of these foods, nor how they act on the human body and how this is associated with exacerbated weight gain.

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.