Answer: The correct answer is -
Eukaryotes.
Eukaryotes are the organisms that possess a true nucleus (containing the DNA, which is the genetic material) and the membrane bound subcellular compartments ( also known as cell organelles) such as golgi complex, endoplasmic reticulum, mitochondria.
As per the given information in the question, cells of mushrooms, plants, and animals all have visible nuclei under a microscope.
Thus, it indicates that these organisms are eukaryotes.
The sun is the ultimate source of energy and the process is Photosynthesis.
The answer is greater omentum. The omentum is a membranous twofold layer of greasy tissue that spreads and backings the digestion tracts and organs in the lower stomach zone. The omentum is comprised of the more prominent omentum which is a vital stockpiling for fat stores and the lesser omentum which associate the stomach and digestion tracts to the liver.