evolution – n. the process by which changes in plants and animals happen over time

fossil - n. remains of an organism from the past

stem cell(s) – n. an unspecialized cell that gives rise to differentiated cells

neuron(s) – n. a cell that carries messages between the brain and other parts of the body and that is the basic unit of the nervous system

emerge(d) – v. to become known or apparent

fascinating – adj. very interesting

origin(s) – n. a cause, rise or beginning

ultimate – adj. greatest or most extreme

relative(s) – n. an animal or plant connected to another by common ancestry

abnormalities – n. things that are not normal or usual, usually in a way that is undesirable or worrying