The petroleum industry uses deep-well injection to dispose of its hazardous waste.
though the wastes are pumped into porous rock, the industry claims the wells are safe because

because they are situated near aquifers

Explanation:

Aquifers is a underground layer of rock which can hold and release water in desirable amounts so petroleum industries claims the well are safe.

your answer is "the 1950's"

in the year 2850, humans successfully colonized mars. the martian modules that were constructed could hold only a small population of people. it is now a century later, and the population on mars has grown to 600 people. of the current mars population, 45 people express the recessive phenotype for phenylketon- uria (pku) syndrome (pp genotype).

explanation: