Which if the following best describes why invertebrates isn’t considered a scientifically valid word when classifying animals

Answer:
I believe the answer is b.
Explanation:
All invertibrates share one charistic in common, they have no backbone.
Answer:
The correct answer is option D.
Explanation:
Invertebrates don’t have a common similarity in an anatomical structure that all have. They are different in their structure so they should not be grouped into one group.
All different groups of invertebrates have a different type of symmetry, composition, and anatomically different but there is not a common character except the fact that no one has vertebra.
Thus, the correct answer is option D.