Which of the following possesses a layered crystal structure?

Which of the following characteristic properties is $NOT$ true for crystalline solids?

Solid $NaCl$ is a bad conductor of electricity since:

Given below are two statements.
Statement $I$ : $O_2, Cu^{2+}$ and $Fe^{3+}$ are weakly attracted by magnetic field and are magnetized in the same direction as magnetic field.
Statement $II$ : $NaCl$ and $H_2O$ are weakly magnetized in opposite direction to magnetic field.
In the light of the above statements,choose the most appropriate answer from the options given below:

Why are amorphous solids called pseudo solids or supercooled liquids?

What is a semiconductor? Describe the two main types of semiconductors and contrast their conduction mechanism.