This figure illustrates 3 hypotheses of how a cancer stem cell may arise: (1) A stem cell undergoes a mutation, (2) A progenitor cell undergoes two or more mutations, or (3) A fully differentiated cell undergoes several mutations that drive it back to a stem-like state.
Adult frogs are on land and they have feet and a body
Tadpoles are in water and they are somewhat like a fish!
Kingdoms are classified into three Domains and into one of the six kingdoms of life.
A vaccine works by training the immune system to recognize and combat pathogens, either viruses or bacteria.
