The layer of the Earth's atmosphere where most planes fly is the stratosphere.
✔ A. Stratosphere
O B. Mesosphere
O C. Thermosphere
O D. Troposphere
<span>False. In order to create a control group one must understand the baseline of what is happening. Therefore placebos are given in order to establish this control group. These control groups allow understanding of what an the actual experimental drug, in the case of clinical trials, can do.</span>
Answer:
Explanation: ground water contamination is nearly
always the result of human activity. In
areas where population density is high and human
use of the land is intensive, ground water is especially vulnerable. Virtually any activity whereby
chemicals or wastes may be released to the environment, either intentionally or accidentally, has
the potential to pollute ground water. When
ground water becomes contaminated, it is difficult
and expensive to clean up.
To begin to address pollution prevention or remediation, we must understand how surface waters
and ground waters interrelate.
The answer is Nucleus. Hope this helps!
