Question

question 40 of 48
suppose the scientists conducted the
experiments again with a third type of plant.
keeping the $\ce{nh4+}$ uptake the same, the
scientists concluded that the $\ce{no3-}$ uptake
of the third plant was higher than the other
plants for every $\ce{nh4+}$ concentration. does
this new data weaken the validity of the
previous data gathered for experiment 3?
a yes, no new experiments could weaken the validity of
previous experimental data.

b yes, the $\ce{no3-}$ uptake and $\ce{nh4+}$ uptake values need not be the
same for all three plant types.

c no, no new experiments could weaken the validity of previous
experimental data.

d no, the $\ce{no3-}$ uptake and $\ce{nh4+}$ uptake values need not be the
same for all three plant types.

Explanation:

To determine the answer, we analyze each option:

• Option A: Incorrect. New experiments can't inherently weaken previous data's validity if the new data is about a different plant (different conditions). Also, the reasoning "no new experiments could weaken..." is wrong.
• Option B: Incorrect. The "Yes" is wrong because new data on a different plant doesn't weaken previous data (which was on other plants).
• Option C: The first part "No" is correct, but the reasoning "no new experiments could weaken..." is incorrect. New experiments with different variables (like a new plant type) don't invalidate previous data from different conditions. However, the better reasoning is about plant types.
• Option D: Correct. The previous data was for two plant types, and the new data is for a third. Since different plant types can have different uptake values, the new data (on a third plant) doesn't weaken the previous data (on the first two plants) because the uptake values don't need to be the same across all plant types. So the answer is D.

Answer:

D. No, the $\text{NO}_3^-$ uptake and $\text{NH}_4^+$ uptake values need not be the same for all three plant types.