1 . While a significant number of jaguars survive here, they are only one element of this forest’s ________ ________.（根据课文内容填空）

2 . At that moment, they felt the earth shaking beneath their feet; beyond in the distance, they heard the ______ of falling roofs. (根据句意填空)

3 . If a scientist is shown a report listing the nutrients of that soil, he or she will probably think that only desert plants can ______ in it!(根据句意填空)

4 . With ______ research, many more medical discoveries like qinghaosu are likely to be made. （根据句意填空）