The $IUPAC$ name of $\beta$-ethoxy-$\alpha$-hydroxy propionic acid (trivial name) is:

The $IUPAC$ name of $CH_3CH_2CH(C_2H_5)COOCH_3$ is

The $IUPAC$ name of $OHC-CH_2-CH=CH-CHO$ is

$IUPAC$ name of the given structure is:

Fill in the blanks:
$(1)$ ....... model indicates only bonds in a molecule.
$(2)$ Only ......... model of a molecule indicates both bonds as well as atoms.
$(3)$ In the nomenclature of cyclic compounds,the ....... prefix is written before the name of the simple chain containing alkane.
$(4)$ The names of $C_{20}H_{42}$ and $C_{30}H_{62}$ are ........... and .......... respectively.

Choose the correct $IUPAC$ name of the compound $CH_3-CH(CH_3)-CH(CH_3)-C\equiv C-CH_3$.