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.
The answer is : randomization was not used in sample selection. The major difference between experimental and quasi-experimental designs is lack of randomization in sampling selection.
Answer:
yes but it can also affect humans like tornadoes destroying homes?
Volcanos spew, ava volcano ash and gases into the environment. this is an effect on the local energy
