Hi! I'd love some clarification on this question

Which of the following are NOT used to classify kingdoms of organisms?

a. complexity of the organism
b. invertebrate or vertebrate
c. method of obtaining nutrition
d. type of cell that makes up the organism
I'm thinking B?

3 answers

Actually, I'm thinking it's A now?
I agree with A.

http://www.ric.edu/faculty/ptiskus/six_kingdoms/
Thank you so much!