What is the best evidence for a three-domain system?

The best evidence for the three domain system is

Sensitivity to Antibiotics

Explanation:

The three domains of life includes :

Archaea - oldest known domain, ancient forms of bacteria.

Bacteria - all other bacteria that are not included in the Archaea domain.

Eukarya - all the organisms that are eukaryotic or contain membrane-bound organelles and nuclei.

Types of evidences for the three domain system are:

1) differences in the sequences of nucleotides in the cell's robosomal RNAs (rRNA)

2) the cells's membrane lipid structure.

3) its sensitivity to antibiotics.

this protocol provides a detailed procedure for nucleoprotein extraction from cultured cells and tissues in an efficient manner.

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!