The first multicellular animals to develop neurons were
A) jellyfish and sea anemones.
B) flatworms and sea urchins.
C) segmented worms and sea horses.
D) mollusks and sea stars.
E) fish and sea monkeys.

Question

Quizplus · Accepted Answer

Jellyfish and sea anemones were some of the earliest multicellular animals to develop neurons. These animals belong to the phylum Cnidaria, which evolved over 500 million years ago and are characterized by their radial symmetry and stinging cells called nematocysts. They are also known as “diploblastic” animals, meaning they have two germ layers, which is a simpler body plan compared to triploblastic animals that have three germ layers.

The First Multicellular Animals to Develop Neurons Were