Yes, flowers are countable. You can quantify them by counting individual flowers, such as saying there are five roses or ten daisies. This makes them a count noun, as opposed to mass nouns, which cannot be easily counted without a unit of measure.
Yes
countable
countable
The noun 'hill' is a countable noun. The plural form is 'hills'.
cookies are countable unless you have brain problems
countable
Shark is a countable noun.
Duck as an animal is countable, but if you mean the meat it is uncountable.
Prawn - prawns is the plural - is a countable noun
countable
few is countable
Countable