La jaula está limpia porque mi hermana la lava cada dos días.

Jaula is a feminine singular noun, so it takes the feminine singular definite article la when you mean the cage.

• la jaula = the cage
• una jaula = a cage

Spanish often uses articles a bit more regularly than English, so starting with La jaula sounds natural here.

Spanish uses estar for a state or condition, and ser for a more essential characteristic.

Here, limpia means the cage is clean right now / in a clean state, so está limpia is the natural choice.

• La jaula está limpia = The cage is clean
• La jaula es limpia would sound unusual here, as if you were describing cleanliness as a defining trait rather than its current condition

So this sentence is about the cage’s condition, not its identity.

Because limpia is an adjective and it must agree with the noun it describes.

• jaula is feminine singular
• so the adjective is also feminine singular: limpia

Compare:

• el cuarto está limpio
• la jaula está limpia

The adjective changes to match gender and number.

That la is a direct object pronoun. It stands for la jaula so Spanish does not have to repeat the noun.

• mi hermana lava la jaula = my sister washes the cage
• mi hermana la lava = my sister washes it

Since la jaula is feminine singular, the pronoun is la.

In Spanish, object pronouns usually go before a conjugated verb.

So:

• mi hermana la lava = correct

Not:

• mi hermana lava la = incorrect

Pronouns can attach to the end of a verb only in certain cases, such as:

• infinitives: lavarla
• gerunds: lavándola
• affirmative commands: lávala

But with a normal conjugated verb like lava, the pronoun goes before it.

Lava is the present simple form of lavar for él / ella / usted.

Here it matches mi hermana, which is she:

• yo lavo
• tú lavas
• él/ella lava
• nosotros lavamos
• vosotros laváis
• ellos lavan

In this sentence, the present tense is used for a habitual action: she washes it regularly.

Because Spanish, like English, often uses the present tense for habitual or repeated actions.

So mi hermana la lava cada dos días means she does this as a routine.

It is similar to English:

• My sister washes it every two days

This is not necessarily happening at this exact moment; it is a regular habit.

Cada dos días means every two days.

• cada = each / every
• dos días = two days

So the idea is that one washing happens, then after two days another one happens.

Learners often connect this with every other day, which is usually a good translation in everyday English.

Because porque as one word means because.

• porque = because
• por qué = why

Examples:

• La jaula está limpia porque mi hermana la lava cada dos días.
• ¿Por qué está limpia la jaula?

So in your sentence, porque introduces the reason.

Yes. That version is completely correct.

• Mi hermana lava la jaula cada dos días
• Mi hermana la lava cada dos días

The version with la avoids repeating la jaula, because it was already mentioned earlier in the sentence.

Spanish often uses object pronouns this way to sound more natural.

Yes, Spanish allows some flexibility.

For example:

• La jaula está limpia porque mi hermana la lava cada dos días.
• Porque mi hermana la lava cada dos días, la jaula está limpia.

Both are grammatical, but the original order is more neutral and natural in most contexts.

Because Spanish marks gender agreement in several parts of the sentence.

Here, jaula is feminine, so that affects:

• the article: la
• the adjective: limpia
• the object pronoun: la

This repetition may feel unusual to English speakers, since English usually does not show gender this often. But in Spanish it is normal and helps connect the parts of the sentence clearly.

Yes. Jaula is feminine: la jaula.

English speakers sometimes wonder about nouns that start with certain sounds because of words like el agua, but that is a special case. Jaula simply takes the normal feminine article:

• la jaula limpia
• una jaula grande

So there is nothing irregular here in terms of article choice.