Which cell would be able to supply itself most efficiently with nutrients diffusing in from the outside—a large cell or a small cell?

The cell with a small size.

Explanation:

The cells exhibiting small size and possessing the surface area and volume ratio, which is proportional to each other would be able to supply itself more effectively with the nutrients diffusing in from the external. The smaller the cell, the more favorable will be the ratio of surface area to volume for the interchange of substances with the environment, which is done via the process of diffusion.  

The volume predicts how much a component enters and leaves the cell, while the surface area predicts the rate at which the nutrients are excreted or are taken in.  

fumikage isn't really a bird, and tsuyu does have teeth. tsuyu has a transformation quirk which still allows her to be partially human. otherwise we'd have a large frog running around. fumikage has teeth because again, he isn't a bird. his head was a quirk mixture if i'm correct.