Question

a researcher studies why frogs are disappearing in the wild. what field of biology does the research fall into?

Answer 1

This would be global ecology. 

This is because "Global ecology" is the study of the interactions among the Earth's ecosystems, land, atmosphere and oceans. Global ecology is very important because it is used to understand large scale interactions and how they influence the behavior of the entire planet, including the earth's responses to future changes.

Hope this helps. :)