Question

A dog enthusiast took home two puppies from the dog shelter. He fed one of the puppies super-premium canned dog food, while he fed the other a generic brand from the grocery store. The dog fed on the generic brand gained weight twice as fast as the dog fed the super-premium brand. Because of the difference in these results, the dog enthusiast concluded that the generic brand actually provided nutrition superior to that of the super-premium brand. Each of the following, if true, would weaken the evidence for the dog enthusiast’s conclusion except for which of the following?

• A. A dog will sometimes gain more weight when eating inferior-quality food because he must eat more of it to obtain the nutrients he needs.
• B. The dogs were of mixed breeds and appeared to be descended from dogs of different sizes.
• C. Both dogs ate all of the food given to them at each serving.
• D. The dog enthusiast did not give the two dogs equal amounts of their respective foods.
• E. A dog will gain more weight when eating inferior-quality food because inferior food is less nutritious.

Hint:

When analyzing experiments, consider factors like food intake and breed differences that could affect the results.

Answer 1

The Correct Option is C

Step 1: Understand the argument.
The dog enthusiast concluded that the generic brand is better because the dog fed this food gained weight faster. However, other factors could explain the results.
Step 2: Review the answer choices.
- (A) This would weaken the conclusion because it suggests that the faster weight gain could be due to the lower quality of the food.
- (B) This weakens the conclusion because mixed breeds of different sizes could explain the weight gain differences.
- (C) This option supports the reliability of the experiment by ensuring the dogs ate the same amount, which keeps the comparison fair.
- (D) This weakens the conclusion because unequal amounts of food would affect the weight gain comparison.
- (E) This would weaken the conclusion because it suggests inferior food could lead to faster weight gain.
Conclusion:
Option (C) does not weaken the conclusion, as it ensures fairness in the food consumption between the two dogs.