Question Detail

BIO 102 Unique characteristics of animals 1 Objective Question

Question

Which two animal phyla are explicitly mentioned as lacking cephalization?
Options
A Platyhelminthes and Nematoda
B Annelida and Arthropoda
C Porifera and Cnidaria
Correct Answer
D Mollusca and Echinodermata
Correct Answer

Option C is the correct answer.

Detailed Explanation

The 'Key Anatomical Features Across Animal Phyla' table, under 'Cephalization', notes: 'Well-developed in flatworms, arthropods, vertebrates; absent in sponges and cnidarians.'

Hint

Consider the simplest animal forms, which often lack a distinct head region.

Question Info