Please help‼️‼️ASAP 12. Scientists may design an experiment with a control group, which is a set of organisms or sam-
ples that do not receive the treatment (the independent variable) that is being tested. Scientists
can then compare normal changes in organisms or samples with those that may have occurred
because of the treatment. The idea of a control group is not the same as a controlled variable.
Suppose a scientist is doing an experiment to determine the effect of an all-organic diet on the
occurrence of cancer in rats.
a. What variables should the scientist control in the experiment?
b. Describe the control group for this experiment.
c. Why is it important for a scientist to use a control group when working with organisms in ar
experiment?

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.