Expressions of quantity tell us how many or how much of something there is.
Compare these two sentences:
We get a little rain in spring.
Many people live in London.
Countable: There are not any biscuits left.
Non-countable: There is not any water in the sink.
Countable: There are no animals in the park.
Non-countable: There is no money in my purse.
Countable: Some children play here on the weekend.
Non-countable: There is some smoke coming from that house.
A lot of
Countable: She has a lot of dogs.
Non-countable: There’s a lot of traffic today.
Countable: Lots of women work here.
Non-countable: She made us lots of coffee.
Countable: There are plenty of bottles in the fridge.
Non-countable: There is plenty of information in report.
Countable: She keeps most of her books in the shelf.
Non-countable: We spent the most time on the project.
Countable: Who ate all the apples?
Non-countable: Jennifer is the one with all the experience.