Which of the following conditions are required for natural selection? I. overproduction of offspring

II. competition for resources

III. genetic variation

IV. natural disasters

I think the answer is III. genetic variation

he movement of air through earth's or any planet's atmosphere is called wind, and the main cause of earth's winds is uneven heating by the sun. this uneven heating causes changes of atmospheric pressure, and winds blow from regions with high pressure to those with low pressure.

i hope this : )

friedrich meischer discovered it in white blood cell