Which of the following substances is a molecular solid?

Select the correct statements.
$(A)$ Crystalline solids have long range order.
$(B)$ Crystalline solids are isotropic.
$(C)$ Amorphous solids are sometimes called pseudo solids.
$(D)$ Amorphous solids soften over a range of temperature.
$(E)$ Amorphous solids have a definite heat of fusion.
Choose the most appropriate answer from the options given below:

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

What type of substance is $TiO$?

Which one of the following elements, when present as an impurity in silicon, makes it a $p$-type semiconductor?

Why are solids rigid?