The pathway through which nutrient are replenished and circulated in an ecosystem is called a

The illustration below is a food chain. Study it and answer questions 29 and 30.
             Grasses → Grasshoppers → Lizards → Hawks

Which of the following statements is not correct about the food chain? The number of 

Grasses → Grasshoppers → Lizards  → Hawks

If the individual species of organisms in the food chain are counted and arranged as a pyramid, the result would be a pyramid of 

Which of the following gases is released during the decomposition of organic matter?

The diagrams above are the illustrations of organisms from different habitat. Study them and answer questions 32 and 33.

The structures labelled I are for