The pictures are the answers here is the question
students studying the plant Brassica rapa want to know at what percent of carbon dioxide (CO2) in the air Brassica rapa will grow fastest. which table shows an experimental design that will best answer the question?

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.

3 1/4 %

explanation:

if you're asking what comes out, it's steam.