Green bristlegrass, sparrows, snakes, wheat, locusts, voles, frogs and cabbage worms can form the following groups of food chains (where "→" stands for being preyed):

1, dog tail grass → vegetable worm → frog → snake

2. Dog tail grass → locust → frog → snake

3. Green bristlegrass → grasshopper → sparrow → snake

4. Setaria viridis → cabbage worm → sparrow → snake

5. Wheat → vole → snake

6. Wheat → Locust → Frog → Snake

7. Wheat → Locust → Sparrow → Snake