Which of the following is not a resonance structure of the others?

Which type of isomerism is exhibited by the following compounds $I$ and $II$?
$(i)$ $CH_3CH=CHCH_3$
$(ii)$ $CH_3-CH(OH)-CH_2CH_3$

Which is the correct structure of trans-$2$-hexenal?

Determine the number of optically active isomers for the given structure.

Which of the following compounds is chiral?

Identify the correct sequence for True and False.
$(I)$ Only compounds with chiral centers can be optically active.
$(II)$ Absence of elements of symmetry is the reason for a molecule's optical activity.
$(III)$ All organic compounds contain carbon $\&$ hydrogen.
$(IV)$ Different canonical forms of a molecule represent the actual structures of a molecule which has resonance in it.