This exercise asks us to answer questions in complete sentences, replacing the direct objects (DO) with direct object pronouns (DO pronouns.) To begin, we need to answer each question in a complete sentence.
The example question is:
¿Tienes la cámara para tomar fotos de los niños?
The complete affirmative answer to the question is:
Sí, tengo la cámara.
Next, we need to identify the DO of the sentence to replace it with the correct DO pronoun.
In the example, la cámara is the DO because it receives the action of the subject - I have the camera, the camera is being had, "having" affects the camera, etc.
Finally, we need to replace the DO with its proper pronoun. Let's review all our DO pronouns for first, second, and third person in singular and plural, and masculine and feminine.
La cámara is third person singular feminine, so it becomes la.
We are answering the question in present indicative - Sí, tengo la cámara - so the DO pronoun always goes directly in front of the verb - Sí, la tengo.
You can repeat this model with all of the questions asked, but it is important to note that questions #2 and #5 are asked in the third person plural - ustedes - so they should be answered in the first person plural - nosotros.
This should be sufficient to completing this exercise...
But if you want to take things up a notch (-; and answer questions #1 and #6 with the option of including the indirect object pronouns (IO pronouns), here are some hints:
IO pronouns are slightly different from DO pronouns, but they are used in a similar way structurally in the sentence.
If the example question we looked at before were to include an IO, for example:
¿Tienes la cámara para tomar fotos para mí?
We would answer:
Sí, tengo la cámara para tomar fotos para usted.
Once again, we can replace la cámara with the DO pronoun la. But we can also replace para usted with an IO pronoun. As usted is third person singular, it becomes le. As it is an IO pronoun, we put it before the DO pronound la before the verb tengo.
Sí, le la tengo - wait, le la tengo? That's kind of a mouthful! And it's also incorrect.
In Spanish, when third person DO and IO pronouns occur next to each other, it can sound kind of weird out loud. So, we change the third person IO pronoun to se, whether it is singular or plural.
So instead of Sí, le la tengo we say Sí, se la tengo.
This can also happen in the infinitive and the gerund.
Estoy tomando esta foto para mi madre - Estoy tomándosela.
Puedo mandarles a ustedes esta foto también - Puedo mandársela también.
But remember, this is only necessary when the DO and an IO pronouns are both in third person!