Answer:
the internal organ in which the major part of the digestion of food occurs, being (in humans and many mammals) a pear-shaped enlargement of the alimentary canal linking the esophagus to the small intestine.
I would choose the mountain ecosystem.
The mountain ecosystem contains a complex living organisms.
Mountain lands support a diverse array of habitats with large range of plants
and animals. It is very crucial for biological diversity and is very wonderful
to see. The climate is mostly cool which is fitting for relaxation.
Answer: Nucleus Acids
Explanation: Nucleic Acids hold and store DNA (think Nucleic/Nucleus)