Why is steel suitable for making permanent magnets?

If a diamagnetic solution is poured into a $U-$ tube and one arm of this $U-$ tube is placed between the poles of a strong magnet with the meniscus in line with the field,then the level of the solution will:

$A$ diamagnetic liquid is filled in a $U$-tube. One arm of the $U$-tube is placed in an external magnetic field with the meniscus in line with the field. The level of the liquid in that arm will

If $\chi$ is the magnetic susceptibility and $\mu_{r}$ is the relative permeability of a ferromagnetic substance, then:

Fill in the blank :
$(i)$ The domain size is ...... .
$(ii)$ The domain contains about ...... atoms.

Statement $I :$ The ferromagnetic property depends on temperature. At high temperature,a ferromagnet becomes a paramagnet.
Statement $II :$ At high temperature,the domain wall area of a ferromagnetic substance increases.
In the light of the above statements,choose the most appropriate answer from the options given below :