Learn Spanish (Latin America): Ellas recuerdan el carro del abuelo.

Recuerdan comes from the verb recordar (to remember). It is a stem-changing verb, meaning the o in the middle changes to ue for most forms in the present tense, including the ellas (they) form used here.

Why does the sentence use del abuelo instead of "abuelo's carro"?

Spanish doesn't use an apostrophe "s" to show ownership. Instead of saying "the grandfather's car", you always phrase it as "the car of the grandfather", which translates to el carro del abuelo.

What exactly is del?

Del is a mandatory combination of two words: de (of) and el (the). In Spanish, whenever de is followed directly by el, they must squish together into the single word del.

Does ellas mean they are a group of women?

Yes! Ellas means "they" but is only used for a group of females. If the group had even one male in it, or if you didn't know their genders, you would use ellos instead.