Questions $78-80$ Refer to this graph that shows the concentration of dissolved gas (parts per million by weight) at different depths in the ocean.
According to this graph,
(A) $\mathrm{O}_{2}$ levels are highest near the surface, and $\mathrm{CO}_{2}$ levels are highest at great depths.
(B) $\mathrm{CO}_{2}$ levels are highest near the surface, and $\mathrm{O}_{2}$ levels are highest at great depths.
(C) Both $\mathrm{O}_{2}$ and $\mathrm{CO}_{2}$ levels are highest near the surface.
(D) Both $\mathrm{O}_{2}$ and $\mathrm{CO}_{2}$ levels are highest at greater depths.
(E) The concentrations of the gases at different depths change with the seasons.
