The correct answer is option c, that is, submarine canyons.
A submarine canyon refers to a steep-sided valley cut into the seabed of the continental slope, at certain occasions, outspreading well onto the continental shelf, possessing almost vertical walls, and occasionally exhibiting canyon wall heights of up to 5 kilometers, from the floor of the canyon to the rim of the canyon, like the Great Bahama Canyon.
The independent variable is the type of food available.<span>The dependent variable is the frequency of each type of beak (or number of birds with each beak type)</span>
