What is the main use of $Quartz$?

Which of the following is a primitive unit cell?

What type of magnetism is exhibited by $MnO$?

Most crystals exhibit good cleavage because their constituent atoms,molecules,or ions are arranged in:

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:

Match the items in List-$I$ with their corresponding items in List-$II$.

List-$I$ (Magnetic property)	List-$II$ (Substance)
$(A)$ Ferromagnetic	$(1)$ $O_2$
$(B)$ Antiferromagnetic	$(2)$ $CrO_2$
$(C)$ Ferrimagnetic	$(3)$ $MnO$
$(D)$ Paramagnetic	$(4)$ $Fe_3O_4$
	$(5)$ $C_6H_6$