Hint:

Singular refers to only one person, animal, place or thing i.e., one. Plural refers to more than one person, animal, place or thing i.e., many.
Most nouns are made plural by adding '-s' to the end of the singular form. Singular nouns that ends in 's', 'x', 'sh', 'ss', form the plural by adding 'es'. When the noun ending with 'y' follows a consonant, it changes 'y' to 'i' and adding 'es'.