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

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.

the dark variety, as they are not visible on the dark tree barks

explanation:

multiplying and dividing the two decimals and the eqations by the same number of the overalls