Which of these, if true, would support the claim that the ancestral cnidarians had bilateral symmetry?
1)Cnidarian larvae possess anterior-posterior, left-right, and dorsal-ventral aspects.
2)Cnidarians have fewer Hox genes than bilaterians.
3)All extant cnidarians, including Nematostella, are diploblastic.
4)β-catenin turns out to be essential for gastrulation in all animals in which it occurs.
5)All cnidarians are acoelomate.
A) 1 only
B) 1 and 4
C) 2 and 3
D) 2 and 4
E) 4 and 5

Question

Quizplus · Accepted Answer

Option 1 states that cnidarian larvae have anterior-posterior, left-right, and dorsal-ventral aspects, which implies bilateral symmetry. Option 4 states that β-catenin is essential for gastrulation in all animals in which it occurs, including cnidarians, which suggests that cnidarians went through gastrulation processes similar to those of bilaterians. Therefore, options 1 and 4 together support the claim that ancestral cnidarians had bilateral symmetry. Options 2, 3, and 5, on the other hand, do not provide evidence of bilateral symmetry. Option 2 states that cnidarians have fewer Hox genes than bilaterians, which is not necessarily indicative of bilateral symmetry. Options 3 and 5 state that all extant cnidarians, including Nematostella, are diploblastic and acoelomate, respectively, but neither trait is directly relevant to bilateral symmetry.

Which of These, If True, Would Support the Claim That