What is the $IUPAC$ name of formic acid?

$(i)$ Distinguish between saturated hydrocarbons and unsaturated hydrocarbons with the help of the combustion process.
$(ii)$ Write the chemical names of $C_{4}H_{10}$ and $C_{2}H_{2}$ and draw their structures.

What is used to preserve the dead bodies of animals?

What is meant by homologous series of carbon compounds? Classify the following carbon compounds into two homologous series and name them.
$C_{3}H_{4}, C_{3}H_{6}, C_{4}H_{6}, C_{4}H_{8}, C_{5}H_{8}, C_{5}H_{10}$

State the meaning of functional group in a carbon compound. Write the functional group present in $(i)$ ethanol and $(ii)$ ethanoic acid and also draw their structures.

Which polymer is formed by reacting a compound containing two carboxylic acid groups and a compound containing two hydroxyl groups?