Question

what inheritance do all animals today owe to cnidarians?
muscles and nerves (movement)
lungs and gills
eyes and hearing
blood and bones

Explanation:

Cnidarians are among the earliest animals with muscle - like cells (myoepithelial cells) and simple nerve nets. These early forms of muscles and nervous systems (for basic movement and response to stimuli) were an important evolutionary step. Lungs and gills are more complex respiratory structures that evolved later in more complex animals. Eyes and hearing (as complex sensory organs) and blood and bones (in the form we know in many modern animals) are not the key inheritances from cnidarians.

Answer:

Muscles and nerves (movement)