The importance of fat in the diets of our ancestors was mainly a result of its energy-storing properties.
Option B
Explanation:
Earlier ancestors or say, hominids ancestor were at the inception of the evolutionary world developed a trend on eating whatever they could find. The ancestors are believed to be scavengers rather than hunters as the evolutionary and nutrition biology suggests.
They had to travel and work for the food and as they were scavengers, it was not guaranteed to have food on a daily basis, so the fat has energy storing properties and for which its importance was realized in the diet. Later when they became hunters, protein became more important in their diet.
I think it's Photosynthesis because photosynthetic bacteria began producing excess oxygen, which added oxygen to the Earth's atmosphere.
I’m not 100% sure but I think there are 2 carbon atoms.
