The________operator can be used to identify an element in the array to be updated without explicitly specifying the position of the element.

Which of the following command inside aggregate command is used in MongoDB aggregation to filter the documents to pass only the documents that match the specified condition(s) to the next pipeline stage.

In a replica set, a_________number of members ensures that the replica set is always able to select a primary.

Which of the following are valid json documents? Select all that apply.

Dada una coleccion, cuales devuelve con la siguiente query
db.coleccion.find({nombre:"ruben",apellido:"gomez"},{nombre:l,apellido:l,aficion:l});