Shield volcanoes have bases and inclined slopes.

Shield volcanoes have BROAD bases and GENTLY inclined slopes. The volcanoes of the Hawaiian Islands are shield volcanoes. These volcanoes are formed from basic or basaltic lava. This lave is relatively lower in silica and as such can flow for great distances and is not sticky. This allows for the formation of volcanoes with broad bases and gentle slopes. 

It would be C because oxygen isn’t used by plants and plants only So that would cross out there, B is wrong because humans can’t do photosynthesis. Plants are the only organism that can carry out Cellular respiration, so that takes out D so the only logical answer to say it is used by organisms to carry out cellular respiration