How Many Tissue Layers are in the Embryos of Sponges

Question

How many tissue layers are in the embryos of sponges?
A) None
B) One
C) Two
D) Three
E) Four

Accepted Answer

Sponges are considered to be one of the simplest types of animals and do not have true tissues or organs. Therefore, there are no tissue layers in the embryos of sponges.