Which expression do you use to "give a reason for the previous point" in IELTS speaking part?

Which expression do you use to "Give an example related to the previous point" in IELTS speaking part?

Which expression do you use to "Add detail to the previous point" in IELTS speaking part?

Which expression do you use to "Introduce an idea that contrasts with the previous point" in IELTS speaking part?

What is the function of saying "On the grounds that,..." in IELTS speaking part?

Concluding an argument with a final point

Contrasting by giving a different perspective/opinion