Cells in onion peels are dead and the ones in spinach are alive.
The correct answer should be
<span>D. Autonomic nervous system
It is called autonomic because it works on its own and it regulates organs functioning which is a thing that happens involuntarily. It regulates heart beats for example and it's not something that you do voluntarily since the heart beats regardless of you. It also controls things like vomiting or sneezing that you can't choose not to do when it starts happening.</span>
Frogs have only one opening, called the cloaca, through which both feces and urine pass. Humans, however, possess two separate orifices for urine and feces to exit through.
