Procaryotes are distinguished from eukaryotes on the basis of what structure? (more than one answer is correct)
a. a membrane-bound nucleus
b. plasmid dna
c. rna molecules
d. presence of mitochondria or chloroplasts

a. a membrane-bound nucleus

d. presence of mitochondria or chloroplasts

Explanation:

Procaryotes are the organisms that lack membrane-bound well-defined nucleus in their cells. These organisms have their DNA present in the cytoplasm itself. Procaryotes also lack the membrane-bound organelles such as mitochondria, chloroplasts, Golgi apparatus, etc.

On the other hand, eucaryotes have a membrane-bound well-defined nucleus in their cells to house DNA in it. These organisms also have membrane-bound organelles in their cells. Examples of procaryotes are bacteria and archaea while animals and plants are eucaryotes.

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!