The correct answer is number 3 I think i am not really sure but I believe so it is
True. we dont have a fully developed brain yet<span />
Answer:
1. Electrical impulses in the heart cause the muscle to contract.
2. To keep the blood flowing in only one direction
Explanation:
In the first question, the correct answer is ''Electrical impulses in the heart cause the muscle to contract''. Every muscle in our body contracts because of electrical impulses and this is also true for our hearts. Or any hearts in nature that we know of.
In the second question, the answer is ''To keep the blood flowing in only one direction''. We have those valves and without them, we wouldn't be able to function as we do.