Is the English three simple form the same as the plural form? For example, if you add es to the complex number of tomato, what does it add to the simple number of tomato?

Is the English three simple form the same as the plural form? For example, if you add es to the complex number of tomato, what does it add to the simple number of tomato?

The simple three is for verbs, and the singular and plural are for nouns, so nouns don't have the simple three form, and verbs don't have the plural form, but most of them add s after them, but some nouns have special cases, such as the plural of mouse is mice