Racing of Bikes That Run on Gas Over Rough Terrain
This page is the CodyCross answer for the clue below from Science Lab, Group 311, Puzzle 5 (Synthesis Reaction).
Question is: Racing of Bikes That Run on Gas Over Rough Terrain
and the answer is: MOTOCROSS
Word Meaning:
MOTOCROSS — (sports, motorcycling) A form of off-road motorbike racing.
Definitions from Wiktionary.