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?
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".