A flask containing photosynthetic green algae and a control flask containing only water are exposed to a cycle of 12 hours of light and 12 hours of darkness. Which of the following statements best describes how the relative dissolved oxygen concentration in the flask with algae will compare to the control flask? A. The dissolved oxygen in the flask with algae will not be different from the control flask at any time.
B. The dissolved oxygen in the flask with algae will always be higher.
C. The dissolved oxygen in the flask with algae will be higher in the light, but lower in the dark.
D. The dissolved oxygen in the flask with algae will always be lower.
E. The dissolved oxygen in the flask with algae will be higher in the light, but the same in the dark.

answer and explanation;

volcanic rocks are igneous rocks which form from lava, molten rock which has been thrust out of a volcano onto the surface of a rocky body such as an asteroid, planet, or dwarf planet.  

plutonic rocks are igneous rocks which form from subterranean chambers of molten rock or magma. plutonic rocks make up the base of continental crust as well as oceanic crust. their slow rate of formation causes them to be coarse grained since there is plenty of time for large crystals to form before the magma solidifies into rock.

the textural difference is that plutonic rocks are more coarse grained than volcanic rocks. plutonic rocks are coarse grained while volcanic are fine grained ; glassey or fragmental. since fine and coarse are adjectives the decision as to whether a rock is fine or coarse grained is generally made on the bases of whether or not the individual crystals can be seen in most if the rock.