Learn Italian: Produciamo la merce e la trasportiamo subito. - We produce the merchandise and transport it immediately.

To say "The merchandise is produced and transported immediately" using the dynamic passive, you would say: La merce viene prodotta e (viene) trasportata subito. Notice how venire is conjugated as viene to match la merce, and the past participles (prodotta, trasportata) must end in -a to agree with the feminine singular subject.

What is the infinitive of produciamo and why does it have a 'c' in it?

The infinitive is produrre (to produce). It is an irregular verb that evolved from an older Latin root, producere. Because of this, it keeps the c in its conjugated present tense forms, giving us produciamo (we produce), produco (I produce), and producono (they produce).

In la trasportiamo, what does la refer to and why does it come before the verb?

la is a direct object pronoun meaning "it", and it refers back to the feminine singular noun la merce. In Italian, direct object pronouns are generally placed directly before the conjugated verb, whereas in English we put "it" after the verb ("we transport it").

Does the word merce exist in the plural?