List four characteristics of homologous series.

(N/A) $(i)$ All members of a homologous series contain the same functional group.
$(ii)$ They exhibit similar chemical properties due to the presence of the same functional group.
$(iii)$ There is a regular gradation in physical properties such as melting point,boiling point,and density with an increase in molecular mass.
$(iv)$ Any two successive members of the series differ by a $-CH_2$ unit or a molecular mass of $14u$.