Define one radian (S.I standard for plane angle)

Define one steraedian(S.I standard for solid angle)

Define a radian.

What meant by one candela? And Which base quantity is measured by this unit? (or) Define one candela (S.I standard for Luminous intensity)

Define th SI unit of electric current. (or) What is one second in SI system of units? (or) Define one ampere (S.I standard for current)

What is the SI unit of amount of substance? (or) What is one mole in SI system of units? (or) Define one mole (S.I standard for amount of substance)