Final answer:
The recent tool that has greatly assisted in the classification of organisms is DNA analysis, which complements traditional methods such as morphological comparison and the use of cladograms.
Step-by-step explanation:
The technique that has recently provided scientists with another important tool for classifying organisms based on their structural similarities and differences is c. DNA analysis. DNA analysis allows for a comparison of organisms at the molecular level, providing insights into their evolutionary relationships. This has been complemented by the use of computer-generated tools such as cladograms, which help visualize these relationships. Due to the advancements in molecular systematics, scientists are able to tune into the molecular data of organisms - analyzing similarities and differences in DNA sequences to reveal genetic lineage and uncovering patterns of evolution that were not visible through morphological data alone. In the event of mutations, such as insertions or deletions, two closely related organisms may appear distinct. However, DNA analysis and new computer programs can iron out these discrepancies, leading to more accurate classifications.
Beyond confirming classifications based on physical characteristics, molecular comparisons have also highlighted errors in previous taxonomical categorizations. The findings from molecular biology contribute significantly to the construction of phylogenetic trees that show how different species evolved from common ancestors. Molecular information, especially that which is unlikely to be shaped by natural selection, offers a more resilient foundation for tracing common ancestry compared to traits that might evolve multiple times under similar environmental pressures.