9. An experiment is described below. A student was interested in comparing sunblock lotions, which contain chemicals that protect the skin from sunburn. The student purchased three different brands of lotion at three different prices and performed an experiment to see which one best protected the skin. The lotions cost $3, $5, and $7 for an 8-ounce bottle. The sun protection factor (SPF) was 30 for all three lotions. The student applied equal amounts of each lotion next to each other on one of her arms. The three areas covered by the lotions were the same size. The student observed the three areas for color change after two hours of Sun exposure. Identify two conditions that were held constant in this experiment. There are three.​

Explanation is in a file

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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.