An animal cell has a nucleus but no cell wall.
Smith is pursuing an ekg technician certification program. He will be one of the healthcare professionals referred to as cardiovascular technologists and technicians. They help monitor heart health on a broader level.
Just like the bacteria, the archaea have evolved a diverse array of metabolic pathways. As extremophiles, their metabolism shows many adaptations to the extreme environments of their habitat. There are facultative and obligate anaerobes and aerobic organisms in this kingdom.
Natural selection is the process that result in the adaptation of an organism to environment by means of selectively reproducing changes in its genotype, or genetic constitution. It is the a key mechanism of evolution. Charles Darwin popularised the term "natural selection" contrasting it with artificial selection, which is intentional, whereas natural selection is not.
To make it simple, let's have a group of beetle composing of green and some are brown as an example. here, there is a variation in traits. Since the environment could not support continuous population growth, not all species can reproduce to their full potential. Green beetles can easily be eaten by other species like birds compared to brown beetles. The surviving brown beetles will then generate brown offsprings because their trait has a genetic basis. Since more brown beetles survive and becomes more common in the population, the process continues until all individuals will eventually be brown. so basically, if you have variation, differential reproduction, and heredity, you will have evolution by natural selection as an outcome.
