| A.The food chain is not easy to be broken. |
| B.The energy of an animal usually disappears when it dies. |
| C.Increasing the links will not break the balance of nature. |
| D.Breaking the food chain is bad for the biodiversity of the environment. |
| A.human activities can be a big threat to the food chain |
| B.we are all responsible for the breaking of the food chain |
| C.natural disasters are hard to break the food chain |
| D.hunting large sharks for meat is beneficial |
| A.explain what the food chain is |
| B.tell us something interesting about Nature |
| C.suggest that we stop eating meat to save animals |
| D.suggest that we not disrupt the natural food chain |