Molecular clocks use rates of mutation to measure evolutionary time.Mutations add up at a fairly constant rate in the DNA of species that evolved from a common ancestor. The more mutations that happened in each lineage, the greater is the differences between these lineages.
Both plant and animal cells have membranes so whatever chemical reactions they have going inside the cell, it is regulated and maintained. Membranes help separate the internal environment from the external environment.
Hope this helps - I'm currently in cell biology so this question is interesting
<span>The theory puts forward the concept that chloroplasts were developed from one form of prokaryotic organisms taken up inside a primordial eukaryotic cell. This is an organism form that uses light energy to divide, this part of its processes became the chloropplast whilst another formed the origin of mitochondria.</span>
