Please see the attached file for the correct answer
Answer:During pregnancy, red blood cells from the unborn baby can cross into the mother's blood through the placenta. If the mother is Rh-negative, her immune system treats Rh-positive fetal cells as if they were a foreign substance. The mother's body makes antibodies against the fetal blood cells
Explanation:
The independent variable is a variable that can be stood alone. So therefore, the independent variable would be how long it takes to parachute.
