If a noun ends in a vowel, make it plural by adding -___.
The definite articles (el, la) also change in the plural form. They become "_____" and "las."
If a noun ends in a _______, make it plural by adding -es.
If a noun ends in -ión, add -es and drop the written _____.
If a noun ends in -z, add -es and change the z to _____.
If a plural noun refers to a mixed group (masculine and feminine), use the _____. (los perros-dogs male and female)