To an evolutionary taxonomist what determines whether two species are placed in the same genus
A. they have similar facial features
B. they share more common ancestors than any other group
C. they share similar mating behaviors
D. they share the same kingdom

Option B. they share more common ancestors than any other group.

Explanation:

Organisms are classified in one group on the basis of similarities and differences between them. In taxonomy, organisms are placed in one group because they share common ancestors so these organisms are closely related to one another in many characteristics such as shape, appearance and genes.

there's the proffessional site that will you.

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!