How does an intrinsic semiconductor behave at $0 \ K$?

$A$ piece of copper and another of Germanium are cooled from room temperature to $40 \ K$. The resistance of . . . . . . .

GaAs is

Explain the change in the energy band structure of an intrinsic semiconductor with temperature by drawing a figure.

The electrical conductivities of $Ge$ and $Na$ are $\sigma_1$ and $\sigma_2$ respectively. If these materials are heated,then:

Carbon,Silicon,and Germanium atoms each have four valence electrons. If their bandgaps are represented by $(E_g)_C$,$(E_g)_{Si}$,and $(E_g)_{Ge}$ respectively,which of the following relations is correct?