El sábado y el domingo
"The saturday and the sunday" are marked wrong and the right answer is "saturday and sunday."
Why is it wrong to interpret the el?
Like Raymond said, but further, EL Sabado or EL Domingo, somewhat idiomatically, are used where English speakers would say ON Saturday or ON Sunday. So, unless it mean ON... then putting in the "the" in the English version would likely be wrong. Hth.
Think of the article in Spanish as almost inseparable from some words, especially the days of the week. So, "el sábado" equates "Saturday," whereas "the Saturday" is only used in very specific cases in English. A similar situation: "DOG is MAN's best friend" is "EL PERRO es el mejor amigo DEL HOMBRE".