order

Question 1

1.)

Answer 1

blood enters left and right atrium

Question 2

2.)

Answer 2

atria contract, blood forced into ventricle

Question 3

3.)

Answer 3

-ventricles contract, force blood out the heart

Question 4

4.)

Answer 4

valves stop blood from flowing backwards into the atria

Question 5

circulatory system

Answer 5

lungs->heart->organs->
organs->heart->lungs