The compounds ${\mathrm{CH}}_3\mathrm{CH}={\mathrm{CHCH}}_3 \mathrm{and} {\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{CH}={\mathrm{CH}}_2$

contain same number of ${\mathrm{sp}}^3-{\mathrm{sp}}^3,{\mathrm{sp}}^3-{\mathrm{sp}}^2\text{ and }{\mathrm{sp}}^2-{\mathrm{sp}}^2$ carbon-carbon bonds

exist together in dynamic equilibrium

are tautomers

are position isomers