The number of primary amines of formula ${\mathrm{C}}_4{\mathrm{H}}_{11}\mathrm{N}$ is (only structural)

Write the IUPAC names of the following compounds: ${\mathrm{C}}_6{\mathrm{H}}_5-\mathrm{N}{\left({\mathrm{CH}}_3\right)}_2$.

Write the IUPAC name of 

Give the IUPAC name of ${\left({\mathrm{CH}}_3\right)}_2\mathrm{N}-{\mathrm{C}}_2{\mathrm{H}}_5$.

Write the IUPAC names of the following compounds,

.

A secondary amine is a/an _______.