Answer:
Physical changes are changes that do not alter the identity of a substance. Chemical changes are changes that occur when one substance is turned into another substance.
Explanation:
Mineral because its not a rock
Reaction rates can be increased if the concentration of reactants is raised. An increase in concentration produces more collisions. The chances of an effective collision goes up with the increase in concentration. The exact relationship between reaction rate and concentration depends on the reaction "mechanism".
Answer:
This question will be answered based on general understanding of how a controlled experiment should be:
The answer is: We must make sure we are testing/changing only one variable, and controling others
Explanation:
A controlled experiment is an experiment in which the independent variable is changed for a particular group called the EXPERIMENTAL group and unchanged for another group called the CONTROL group.
In a controlled experiment, only one variable should be tested while the others should be kept constant in order to have an effective result or outcome. This is the case in this question, the type of music or soil should be unchanged for each plant because the experimenter must make sure that he/she is testing/changing only one variable, and controling others.