Please please please help me answer this​

Assume similar data for the motion of the blood in your aorta. estimate how many beats of the heart it will take the blood to get from your heart to your brain. (assume that the distance from your heart to your brain is 30 cm)

The long handle on a rake is a(n) a. lever b. screw c. wedge d. inclined plane

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.