Fill in the blank in the following sentence with the appropriate form of the verb lavarse below
los ninos las manos

Los niños _SE LAVAN_ las manos

Explanation:

Los niños _SE LAVAN_ las manos

("The kids wash their hands")

When you conjugate a reflexive verb (like 'lavarse'), you have to use the pronoun in front of the verb. So, indicative present of lavarse is:

Yo me lavo ...las manos

Tu te lavas ...las manos

Él se lava ...las manos

Nosotros nos lavamos ...las manos

Vosotros os laváis   ...las manos

Ellos se lavan  ...las manos

That way, it indicates the action is done on the person itself, not on others ('Yo lavo las manos' - I wash the hands - could be performed with anyone's hands).