<u>d) observing how the heart contracts to pump blood
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Yes it does the chemicals in whatever you are smoking are more than likely altered from what it originally was, therefore the chemicals start to taint the blood vessels and damage them permanently.
we know that
the surface area of the top of the water
is calculated with the formula of the area of a circle

Step 1
Find the radius of the water tank in the middle of the tank
by proportion

so
For h=5 m
the radius is equal to r=1.5 m
Step 2
Find the surface area


therefore
the answer is
the surface area of the top of the water is 
9 weeks is the answer ik health :D