1. A researcher had 15 pure bred wild mice which were brown and all were females. They were all mated with a male called Bob. All the offspring were brown. These were then crossed among
themselves with the following results: 293 brown and 115 white.
(i). Determine the colour of Bob.
(ii). Determine which colour is dominant.
(iii). Work out the ratio of brown to white in the 'grandchildren.'
(iv). If the researcher crosses two of the white 'grandchildren', determine the colour of their
offspring​

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.