A scientist researching methods to convert used motor oil into gasoline would most likely be investigating which process? joining molecules into longer chains
breaking molecules into smaller chains
changing straight chains into rings
changing rings into straight chains

joining molecules into longer chains

Explanation: The scientist is adding two items together, which makes molecules join. This creates longer chains in the mixture. The answer is joining molecules into longer chains. Hope this helps!

that's what i got you can count the number of atoms