题目选项分析

Both the complexity of the phenomenon known as extinction and the vastness of the biosphere have prompted many scientists to call for a large increase in the number of biologists working both in the field and in laboratories to clarify the relationships among the planet's many endangered life-forms.

Both the complexity of the phenomenon known as extinction and the vastness of the biosphere, having prompted many scientists to call for a large increase in the number of biologists working both in the field and in laboratories to clarify the relationships among the planet's many endangered life-forms.