Q.

Which of these is NOT a correct sequence of a food chain

1 Phytoplanktons → Zooplanktons → Fish  
2 Seed grains → Rodents → Eagle  
3 Grass → Insects → Frog → Snake  
4 Seaweed → Zooplanktons → Phytoplanktons  

Ans.

(4)

Phytoplanktons are the primary producers. They should occupy the first trophic level in the aquatic food chain.