Darwin's theory of adaptation follows from three postulates and is termed the process of evolution by natural selection. identify these postulates.

The first postulate is that while a population has the capacity to bear an infinite number of offsprings, this is infeasible since the environment/habitat has limited number of resources hence can only support a finite number of the population depending on the resources available. The second postulate indicates that in a population, there exist variations in traits with some more beneficial than other for survival in the environment.  The third postulate states that only the individuals with the superior traits will produce offsprings over generations and preserve their traits in the population.  

the answer to you question is   jet streams

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.