Group of people could have a very specific challenge having to do with the person or the task - need to watch the same person to see how they change; Ex: some type of physical or cognitive challenge and want to see their progression
Hope this helps
Answer:
D is the answer
Explanation:
Hydraulic facturing, aka fracking, uses toxic chemicals above some regulations which may lead to a leak into water supplies and therefore contaminate it.
It has not much to do with coal, more to do with oil and natural gases
Because of fracking now making it accessible to reach sources in vast number that were previously unacessible, it leads to decreases in gas prices
Hope this helps :)
Homogenous mixture, or a solution.
Needs a better description, but i am happy to help you if you need it !
Velocity
...................
