If all living systems, not plants, have blood; then why do blood types matter?

Prevent risks

Explanation:

The importance of knowing your blood type is to prevent the risk of you receiving an incompatible blood type at a time of need, such as during a blood transfusion or during surgery. If two different blood types are mixed, it can lead to a clumping of blood cells that can be potentially fatal.

because when humans get blood transfusions they need the same type of blood in their body or they will reject it and die.

Explanation:

each blood type has certain antigens and antibodies that will only accept a certain blood type. type O can give to all blood types (A,B,AB,O) but can only receive from type O. Type AB can receive from A,B and O because it has both A and B antigens. if you were to give type A to a type B person the type B antibodies would attack the foreign type A with its anti-A antibodies.

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.