E. coli is a species of bacteria that causes many different infections in humans. Certain E. coli strains have developed resistance to antibiotics, making infections with these strains difficult to treat. How do bacteria such as E. coli, which reproduce asexually, gain new traits such as antibiotic resistance? A. by adapting to changes in environmental conditions without undergoing changes in their DNA
B. by mutating their DNA in response to environmental conditions to gain beneficial traits
C. by producing offspring with new gene assortments from genetic recombination, which increases diversity in a population
D. by undergoing spontaneous mutations when they replicate, which increases genetic variation in a population

brown

explanation:

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!