The lateral hypothalamus signals an animal to start eating, whereas the <span>ventromedial </span>hypothalamus signals the animal to stop eating. So the correct option is the first one.
The correct answer to this question is this one: they lacked oxygen. The earliest organisms were completely heterotrophic in nature because of the reason that they lacked oxygen. <span>A heterotroph is an organism that cannot fix carbon and uses organic carbon for growth. </span>
It's usually d,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,