The difference between "pasta", "sauce", "ketchup"

Tomato "paste", "sauce", and "ketchup" differ in that the paste is semi-solid, and the sauce and ketchup are fluids, but they differ in the presence or absence of additives.

1, paste is concentrated tomato sauce, red semi-solid. The word sounds like a toothpaste, it is very thick, so you must use this for stews and hot pots, otherwise the taste will be very light. Inside the paste is the tomato, there is no salt, sugar or something.
2, sauce is processed with paste, into a fluid, and some are the juice squeezed by the tomato.
3, ketchup is added with flavoring, there are many kinds of flavors, sweet, spicy or something, generally used for salads, as well as snacks with French fries.