The entropy of a perfectly crystalline solid at absolute zero is

Identify the correct statement regarding entropy.

Fill in the blanks given below:
$(i)$ : The scientist who stated that the entropy of a perfectly crystalline substance decreases with a decrease in temperature is .......
$(ii)$ The statement that the entropy of a perfectly pure crystalline substance is zero at absolute zero temperature represents the .... law of thermodynamics.
$(iii)$ The entropy of one mole of a substance at a fixed temperature and standard state is called ..........
$(iv)$ The unit of molar entropy is .........

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.

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

If the entropy of a solid is greater than zero at $T = 0 \ K$,it is called: