Three questions in the field of enterprise system

I’m trying to learn for my Computer Science class and I’m stuck. Can you help?

Qََََ1-Would an enterprise create their own Enterprise system, or would they build it based on packaged software? Justify your answer.


Q2-By your own words explain define the term “ontology “and why do we need to use ontology in enterprise system? list the four levels of the REA ontology and what type of pattern exists at each level?

Q3-What are the differences between Value System Level and Value Chain Level? Give an example of Value System and Value Chain for a company named “electro” manufactures electromenagers.

I hope that your answer is as required in each question and is accurate