Here is more information for beginners related to the definite article in Spanish.
Feminine nouns that start with a stressed a- or ha- use the masculine definite article EL in the singular, not LA.
Since they are feminine, in the plural there is no change and the feminine form LAS is used.
When there is an adjective between the definite article and the noun, the feminine form LA is used.
Here are a few examples:
el agua → las aguas (water) → la fría agua, etc.
el águila → las águilas (eagle)
el alma → las almas (soul)
el ave → las aves (bird)
el ala → las alas (wing)
el hacha → las hachas (axe)
el hambre → las hambres (hunger)