Final answer:
Both a humpback whale and a basking shark are classified under the Kingdom Animalia and the Phylum Chordata, sharing the characteristics of being multicellular eukaryotic organisms and having a backbone.
Step-by-step explanation:
The taxonomy classifications that are the same for a humpback whale and a basking shark are that both are in the Kingdom Animalia and the Phylum Chordata. Even though their evolutionary paths split long ago and they belong to different classes (Mammalia for the whale and Chondrichthyes for the shark), they both share a vertebrate backbone, which is a characteristic of the Chordata phylum. Furthermore, both animals are part of the kingdom Animalia, which encompasses multicellular, eukaryotic organisms that are primarily heterotrophic.
Additionally, both the humpback whale and the basking shark are part of a broader group called vertebrates, which are animals possessing a backbone. This grouping further underscores their similar classification despite the vast differences in their biology and habitats.