Hay (There are) ________ gatos en la casa.
Las?
No.
How do you tell if it is supposed to be feminine or masculine?
Look it up in a Spanish dictionary. Or Google the English translation.
gato ends with o
Hay gatos en la casa.
To answer this question, you need to identify the correct form of the word "las". In this case, "las" is a feminine plural form of the article "el" or "la" in Spanish. Since the word "gatos" is a masculine plural noun, the correct answer would be "Los", which is the masculine plural form of "el" or "la".
Therefore, the correct sentence would be: "Hay LOS gatos en la casa."