Cual es la principal característica de las actividades del sector terciario

Atown is built on the banks of a small lake on the edge of a desert. after some time, the townspeople discover that water from the lake has become too polluted to use. describe one way that the lake may have been contaminated by the actions of the townspeople, and explain how the townspeople can remediate this problem.

Stages 1 and 4 of the demographic transition are similar in that

Find the coordinates of a if b(-9,-10) is the midpoint of ac and c has the coordinates of (-1,9)