C. fluid
is the correct answer
Glucose + Oxygen > Carbon Dioxide
C(6)H(12)0(6)+ 0(2) >CO(2)
Happy Holidays! :)

Looking at the information given in the description, the experiment is testing for the effects of the different salts on the growth of the plants.
This means that the type of salt is the independent variable, or the variable being manipulated and tested.
To ensure fair results, some parts of the experiment would need to be kept the same, which is the control. The only answer choice that makes sense in this instance is A. water.
IT will be easy to know how chemical reactions occur
It will helps to know the fundamental particles of an atom