Final answer:
The determination of phylogeny is based on the c) evolutionary history of organisms, using morphological and genetic data to construct phylogenetic trees and determine evolutionary relationships.
Step-by-step explanation:
Phylogeny is determined using evolutionary history, which includes assessing morphological, genetic, and molecular data to map the evolutionary pathways of all life on Earth. Scientists use phylogenetic trees to illustrate evolutionary relationships based on these data. They analyze homologous characteristics and genes, distinguish these from analogous features using modern technologies, and often apply cladistics and the concept of maximum parsimony to organize this into an evolutionary timeline.