Surface to volume i think
Plankton exists near the bottom of the ocean's food chain and provides nutrition for whales, shrimp, snail, and jellyfish. Plankton also plays an important role in the carbon cycle by removing inorganic carbon dioxide due to photosynthesis.
B.) Ulnar aspect of the hand
Because the molecules that are being transported is moving against its concentration gradient. in other words, its moving from where its low in concentration to where its high in concentration