4. Alkanes and Cycloalkanes

Which of the following best describes the structure of $1,4-\mathrm{dimethylcyclohexane}$?

Which of the following compounds is a $\mathrm{cycloalkene}$?

Which of the following correctly names a $\mathrm{cyclohexane}$ ring with $\mathrm{methyl}$ groups at carbons $1$, $3$, and $5$, assuming the lowest possible set of locants is used?

What is the correct IUPAC name for a cyclohexane ring with a methyl group at carbon $1$ and an ethyl group at carbon $3$?

Which of the following molecular formulas corresponds to a cycloalkane?