Can you rephrase your question?
Answer:
1. Voy a hacerla.
2. Necesitamos llevarlos.
3. Marcos lo está pidiendo / Marcos está pidiéndolo.
4. Javier debe llamarlos.
5. Ellos desean visitarlo.
6. Puedo llamarlo por la mañana.
7. Prefiero llevarla.
8. No queremos perderlas.
Explanation:
It is called a direct object (in traditional grammar, direct complement) to the function played by a syntactic constituent (phrase, pronoun or a substantive subordinate proposition), different from the grammatical subject, which is necessarily required by a transitive verb
It is the person or object on which the action expressed by the verb falls, it is a modifier of the predicate. The direct object can be expressed by pronouns: lo, la, los, las. Substituting the direct object of a sentence for one of these pronouns is a recommended way to verify that it is indeed the direct object.
It would be "Diana prefiere que nosotros tragamos la comida para las vacaciones" because you have to conjugate the verb "tragar" for Nosotros, so you would replace the "-AR" ending with "Amos".