There are several measure to describe the distribution of some observations. The mean for example give an idea about the average observation. The measure that gives us an idea about variability is the standard deviation; Intuitively it measures how much observations differ from the average.
The answer is I, evolutionary phylogeny; It is based on the phylogeny of organisms which is determines the similarities and differences in their physical or genetic characteristics. A phylogenetic tree or evolutionary tree is used which shows the inferred evolutionary relationships among various biological species or other entities.
Fatty acids are important for the cell membrane because the fatty acids present in membrane is cholesterol which provides the fluidity and mechanical support to the cell membrane.
Weather the temp is high or low