Comparison of items eaten for food is the least useful technique to help scientists to determine whether two different animal species have evolved from a recent common ancestor
Step-by-step explanation:
A recent common ancestor (RCA) is the species referred in Genealogy which refers to the very recent individual organism from which a set of organisms is descended. It defines the gene ancestry of an organism.
An evolutionary tree depicts the factors which can be used to relate two species based on evolution through evolutionary relatedness like feeding ecology and distribution of the organisms geographically.
Comparison of items eaten for food and feeding ecology of animals helps to identify RCA.
Mapping the lineage of dietary shifts or changes in foods eaten by among organisms (meat-eating or herbivores) adapted due to environmental adaptations by studying and comparing eating habits or behaviors can help to trace the RCA .