Heart problems often cause trouble breathing. which best explains this?
explain why you chooses your answer
a the heart provides the lungs with oxygen.
b the lungs use the circulation caused by the heart
c the lungs are the organs that bring carbon-dioxide into the body
d white blood cells are produced by the lungs

Johnny rode his bike to a friend's house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was not able to play. what was his displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point

What type of pollution does household garbage cause

Suppose you could go back in time to interview henri becquerel on the day he discovered radioactivity. from his perspective, write an account of the discovery.