What is the unique property of carbon that makes organic chemistry a separate branch of chemistry?(catenation/isomerism)

Which classes of organic compounds are often used in our daily diet?

Draw the structural formula of ethane.

Draw the electron-dot structure of propane.

(i) Observe the compounds $\left(\mathrm{a}\right)$ to $\left(\mathrm{e}\right)$

(ii) Identify the compounds those contain a ring of carbon atoms only.

(iii) Identify the compounds in which ring contains at least one atom other than carbon.