Answer:
To regulate body activities (like growth and immunity) by sending chemical messages
Explanation:
I'm not 100% sure about this, but this seems most likely after a quick internet search.
I hope this helps, but you might want to double-check this.
Answer:
B. Constants
Explanation:
Constants are the factors that stay the same throughout the entire experiment no matter which group. The definition of a constant is "a situation or state of affairs that does not change." this furthers the point that constant is the correct answer because they don't change in the experiment.
Immigration followed by competition
I hope this right, if its not, sorry =)
