C. Medusa. Everything else on the list is a part of another creature, medusa is the only cnidarian here!
Nerve cells or neurons are, fundamentally, cells of the nervous system, they are responsible for the transmission of nerve impulses and communicate with one another through connections called synapses .
Neurons are typical of all vertebrates, although in the rest of the animal kingdom there are other cells that have similar functions.
So, the right answer is A. Horse.
The extinction of owls would increase the grasshopper population because the owls would not be eating any grasshoppers allowing the grasshoppers to reproduce and stay alive longer.
