There is/are is an expression used in sentences that confirm, deny or check that something exists:
- When used in affirmative, it confirms that something exists;
- When used in negative, it denies that something exist;
- When used in interrogative, it ask if something exist.
Determiners are modifiers of nouns.
They can provide information about which and how much/many people, things… we are talking about.
Quantitative determiners or quantifiers are used to indicate the quantity of something.