Modern systematists try to group organisms based on

a. size.
b. evolutionary relationships.
c. ecological niche.
d. physical appearance.

B. evolutionary relationships.

Explanation:

Systematics is biological study of the relationships among living things through time. It is  used to understand the evolutionary history of life. Usually, relationships among organisms are presented and vizualized through the evolutionary trees. Branching of the tree shows group relationships while branch length shows amount of evolution.

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.

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