How can natural selection account for the long snout of an anteater ?

First of all, the purpose of natural selection is to "weed out" the organisms in a species with imperfect qualities.  Basically, it's evolution's way of making the species that best it can be.

An anteater eats insects (namely, ants) by sticking its snout and tongue through anthills and the ground.  Obviously, the longer the snout of the anteater, the more possible bugs it can reach and, therefore, eat.  So, over millions of years, anteaters with shorter snouts were not able to reach enough bugs and ended up dying.  The anteaters with longer snouts had more food available because they could reach more bugs, so they were able to live long enough to reproduce and produce offspring with the preferred trait:  having a longer snout.

Nine months old i think but i’m not that sure

The open ocean begins at the low-tide mark and extends to the end of the continental shelf

above statement is not a true statement about the open ocean because the open ocean has low levels of nutrients. most of the photosynthetic activity on earth occurs in the open ocean within the photic zone. organisms in the deep ocean are exposed to frigid temperatures and total darkness but it does not begin at the low-tide mark.