Which of these is purposefully changed during a scientific investigation? a test variable (independent variable) b outcome variable (dependent variable) c control group d hypothesis

The independent variable is the only one that can change. Outcome variable depends on the test variable, so it isn't purposely changed. The control group isn't changed, because then it wouldn't be a control. And if you changed the hypothesis, you would basically be cheating and saying you knew what would happen before the experiment.

A. Test variable (independent variable)!

Explanation:

metamorphism is the change of minerals or geologic texture (distinct arrangement of minerals) in pre-existing rocks (protoliths), without the protolith melting into liquid magma (a solid-state change). the change occurs primarily due to heat, pressure, and the introduction of chemically active fluids. i hoped i !

glycolysis is a process that fuel your metabolism. it is apart of cellular respiration the process that produce atp.