Simplify the following text for a Grade 13 native English-speaking person.
Original: This space overlaps three nations , Afghanistan , Iran , and Pakistan , whose mountainous peripheries define the crescent , though only Afghanistan and Pakistan produce opium , with Iran being a consumer and trans-shipment route for the smuggled opiates .
Simplified: This space overlaps three nations , Afghanistan , Iran , and Pakistan , whose mountainous peripheries define the crescent .