Answer:
I believe the answer is "b". "During the experiment, the scientist has only one element, or variable, that is changed to test the hypothesis."
Explanation:
I remember from last year but I'm not totally sure. Good luck!
Answer:
activation energy hope this is right
Both are caused by human ignorance. Both have the ability to kill those in them. Both can become compact to create new material.
C is the correct answer since it outputs and inputs chemicals
