Question

what does \mountainous\ mean? facts about mountains parts of mountains having many mountains across from mountains

Explanation:

To determine the meaning of "mountainous", we analyze the word structure. The root "mountain" refers to a large landform, and the suffix "-ous" typically means "full of" or "having the quality of". So "mountainous" should mean having many mountains. Let's check the options: "facts about mountains" is about information, not the meaning of the adjective; "parts of mountains" is about components, not the meaning; "across from mountains" is about location, not the meaning. Only "having many mountains" fits the meaning of the adjective "mountainous".

Answer:

having many mountains