Una pieza de roca áspera. I'm only guessing <span />
Answer:
It occurs in organisms because an organism with a beneficial trait/mutation have a higher chnace of surviving compared to organisms that do not. So the organsims that do survive pass on their genes to the next generation, and the bext generation will pass on those genes to the generation after and so on. But all the organisms that do not possess a beneficial trait/mutations will not survive, therefore they cannot reproduce and pass on those genes to their offspring. This means that most of the population will posses that trait/mutation.
Example: Spotted moths camouflage with bark so they are seen by predators and eaten. Black moths are easily seen by predators and are eaten. Spotted moths then pass on their genes to the next generation of moths.
The answer is C. A theory is an idea intended to explain why something happened. It may have not been proven correct e.g. Darwin's theory of evolution
Carbon and hydrogen.
The simplest group of organic molecules are the alkanes which have only these 2 elements. Eg methane, CH4.