A model organism is a species that has been widely studied to understand a particular biological phenomena, normally used because they are easy to breed and maintain in a laboratory setting and has certain experimental advantage.
The criteria that Thomas hunt Morgan was looking for include; the model organism should be small in size, easy to keep in the laboratory and also able to produce large number of off springs in a short time.
The rock cycle<span> is a model that describes the formation, breakdown, and reformation of a </span>rock<span> as a result of sedimentary, igneous, and metamorphic processes. All </span>rocks<span> are made up of minerals.</span>
A dominant trait will mask a recessive trait.
