The geological timescale was first developed using the fossil record, but this provided only a system of relative dating; absolute dates weren't established until the discovery of: -

... radioactive decay.

Explanation:

Radioactive decay

Explanation:

Radioactive decay which is a property of several elements found on the earth involves the emission of charged particles and energy of unstable nuclei of radioactive atoms, thereby becoming stable with time. The rate of radioactive decay is often referred to as half-life of that element, and could be as more than millions of years. Radioactive elements that undergo radioactive decay have made it possible for a more accurate dating to be achieved using the known decay rates of radioactive materials.

type 2 happens when excess consumption of high-sugar foods flood the blood supply with glucose and reduce the production and effectiveness of insulin. if a person has prediabetes, they can reduce the risk of full diabetes through regular exercise and a balanced, low-sugar diet.

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.