"A aranha dos meninos"

Whatever the meaning, the children' is wrong; it requires a terminal 's' to make the possessive since the noun is, already, plural.

the spider belongs to the boys Oops, that’s wrong Correct solutions: The spider of the boys The boys' spider

how's that any different?? it's getting really difficult trying to keep up with what the program wants; a literal or a more meaningul answer

Good

Can somebody please explain dos to me? It would be really helpful. Thank you.