Answer:
C.
Explanation:
If the students want to know at what percent of CO2 in the air the plant will grow at the fastest, then the percent of CO2 should be a different value for each plant in the table.
There are 2 tables that have different values for the CO2 - the tables in answer choices C and D.
Since the students only want to know how the amount of CO2 affects the plant, every other variable should remain constant.
The only answer choice that has a changing value for the percent of CO2 and a constant value for every other variable is C.
Answer:

Explanation:
Hello!
In this case, when two substances at different temperature are put in contact and an equilibrium temperature is attained, we can evidence that the heat lost by the hot substance (metal) is gained by the cold substance (water) and we can write:

Which can be also written as:

Thus, since we need the specific heat of the metal, we solve for it as shown below:

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