In this task, you are given a question and answer for that. The answer will fill in the blank or will complete the unfinished question. Your task is to provide an explanation based on the given question or fill-in-the-blank statement, and answer.

Q: Question: Olive and Jean were collecting rocks during a hike, they collected too many rocks so the two girls decided to leave some rocks behind to come back to later. Olive decided to bury her rocks in the dirt, and Jean decided to leave hers in a ditch in the sun. When they returned a week later, which girl's rocks changed the most? 
 Answer: Olive

A: With more surfaces of the rocks exposed, there are more places for chemical weathering to occur.
****
Q: Question: Jim's skin was noticeably darker than his friend Matt's skin. This means that _____ produces more melanin. 
 Answer: Jim

A: However, the melanocytes of people with darker skin produce more melanin.
****
Q: Question: If a car and a truck drive closer to each other, what happens to the gravitational attraction between the two vehicles? 
 Answer: increases

A:
As the distance between the objects increases, the force of gravitational attraction decreases.
****