Learn Italian: La mucca che vedi nella fattoria dà molto latte. - The cow that you see on the farm gives a lot of milk.

It is acting as a direct object. The subject of the action vedi (you see) is "you", so che represents the cow being seen. In Italian, che is extremely versatile: it is used for both people and things, and it can be either the subject or the direct object in its clause.

What is the subject of the verb dà (gives)?

The subject is La mucca (The cow). The core of the sentence is "The cow gives a lot of milk" (La mucca dà molto latte). The relative clause che vedi nella fattoria is simply inserted into the middle to tell us exactly which cow we are talking about.

Why does the word dà have an accent mark?

The accent mark shows that it is the verb meaning "gives" (the he/she/it form of dare) rather than the preposition da (from/by). Because these two words sound exactly the same, the written accent is required so you know which one is being used.

The translation says "on the farm", but nella translates to "in the". Why?

Prepositions often do not translate directly between languages. While English speakers say someone or something is "on" a farm, Italians say they are "in" a farm. Here, the preposition in is combined with the article la to make nella (in the).