The over-prescription of antibiotics since the 1940s has promoted the evolution of antibiotic resistant strains of many bacterial infections. this process can best be described as what kind of evolutionary force? (genetic bottleneck, genetic drift, founder's effect, natural selection, directional pressure.)

Antibiotics are the medicines which prevent and treat the bacterial infections by inhibiting their growth. Antibiotic resistance is the potential of a bacterium to withstand the effects of an antibiotic. It is a consequence of evolution through the process of natural selection. It occurs through the genetic mutation and the bacteria evolve through natural selection. The widespread use of the antibiotics has made many bacteria resistant through the process of evolutionary pressure driving natural selection. The bacteria carrying the genetic mutation of antibiotic resistance survive and reproduce passing the trait to their offspring.  

there's the proffessional site that will you.

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.