Answer:
Margarita las toma. 
 La voy a usar más tarde. 
No lo puedes verlo ahora. 
Sí, los entendemos. 
Lo está leyendo al lado de la piscina. 
Step-by-step 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.