Answer:
It is necessary to separate oxygenated and deoxygenated blood separate in mammals and birds to maintain their body temperature. Also, if they both are mixed, the blood will get impure and it would be difficult for the heart to supply impure blood. We also can't live with impure blood so we most probably will die.
C
Brown algae
Im pretty sure this is correct
B. The amount of waste would build up and the toxins produced would harm the animals and humans
Answer:
They break down material that are dead or unused and turn them into nutrients in the fields or soil that plants use to grow.
the correct word is decomposers*
