Which of the following is a potential obstacle to the commercial development of brownfields?
a. the presence of pollutants
b. environmental cleanup laws
c. the costs of environmental cleanup
d. all of the above

 d) all of the above

"The presence of poisons", "ecological cleanup laws" and "the expenses of natural cleanup" are all a potential impediment to the business advancement of brownfields. The right alternative among every one of the choices that are given in the inquiry is the fourth choice i.e all of the above

for 8 am not sure maybe yes?

for 9 if it is asking if the male is more or less it would be less

hope i even just a little : )

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.