It was plants. Plants used photosynthesis, basically the sun's energy. And other animals ate the plants, and other animals ate the animals that ate the plant.
Enter stationary phase of the bacterial growth curve. The rate of death of the bacteria is equaled by
the rate of replication. This is due to the stiff competition of the individuals
for the scarce nutrients. The bacteria begin to produce inhibitory molecules that also
increase the rate of mutations among the bacteria due to the harsh environment.
Ok idk if there was a picture that was supposed to go with that cause I don't see one but here are some vestigial structures in humans: Appendix, Pinky toe (debatable possible used for balance) , ear muscles, tail bone, wisdom teeth, nictitating membrane, male nipples (sorry to be gross), and goosebumps. Those are the ones I can remember. Hope this helps!
The three types of symbiotic relationships are commensalism, mutualism, and parasitism.
Commensalism: One organism benefits from the symbiotic relationship while the other remains unaffected. Example: Barnacles and whales.
Mutualism: Both organisms benefit in the symbiotic relationship. Example: Humans and the bacteria in their digestive tract.
Parasitism: One organism in the symbiotic relationship benefits at the other organism's expense. Example: Fleas and dogs.
