The entropy of a perfectly crystalline solid at absolute zero is

State the third law of thermodynamics.

Identify the correct statement regarding entropy.

Which law of thermodynamics helps in calculating entropy at different temperatures?

Identify the correct statement regarding entropy.

Fill in the blanks:
$(i)$ The standard enthalpy of formation of any element in its reference state is considered to be $.........$.
$(ii)$ The scientist $.........$ stated that the entropy of a perfectly crystalline substance decreases with a decrease in temperature.
$(iii)$ At absolute zero temperature,the entropy of a perfectly crystalline substance is zero. This statement represents the $.........$ law of thermodynamics.