SD SAP Variant Configuration questions

Hello guys, I'm preparing for an exam and trying to find the answers for the following questions, please help me, I need them as soon as possible, full points will be given to any answer, Thanks all !

- What is variant configuration?

- What is characteristic?

- What is value?

- What is class?

- What is configuration profile?

- What is dependency and what are the types?

- What is a variant table?

- And the transaction codes for the above.