Because they use it for us people to know what is happening.
Answer:
D. i believe.
Explanation:
A makes sense but there are really deep lakes too, so that is not correct
b doesn't make sense because, they are both habitats , so this is not correct
C makes sense but there can also be above water resources at ponds and lakes too
D makes sense because mostly, ponds/lakes don't have currents, while oceans do
Have a good night!!
-Red
