Question

in 1974, mexican chemist mario molina and us chemist f. sherwood rowland discovered that chemicals called cfcs were harmful to the ozone layer. their research was extremely influential in the fight against cfcs. ______ it laid the foundation for a 1987 treaty that phased out the use of cfcs across the globe. which choice completes the text with the most logical transition? a) regardless, b) specifically, c) however, d) earlier,

Explanation:

The second - sentence provides a specific example of the influence of their research (the 1987 treaty). "Specifically" is used to introduce a more detailed or particular example. "Regardless" indicates despite something, "However" shows contrast, and "Earlier" refers to a previous time, none of which fit the logical flow here.

Answer:

B. Specifically