A particular single-celled organism uses radiant energy to fix carbon as sugars. This organism generates ATP by breaking down sugars through a process that uses oxygen. This organism is aerobic autotroph.
Autotrophs produce their own food from the substances available in their surroundings using light through photosynthesis or chemo-synthesis.
A parasite could determine the size of the population. Whether it grows or shrinks. It could also change genetics
To preserve and keep them fresh
The answer is relative dating.
The abdominal cavity is the answer you are looking for.