Which of the following may happen to astronauts when they return to Earth from space? (1 point)
They may feel dizzy because the flow of blood to and from the heart to the brain is affected in space.
They may feel dizzy because the heart pumps more blood per beat on Earth than in space.
Their heart rate may slow down because there is more blood to circulate around the body.
Their heart rate may slow down because there is less blood to circulate around the body.
