Asocial scientist is trained to study the contents of garbage heaps. "what can we learn from studying garbage? " would most likely be asked by

The answer is Anthropologist
Anthropology is the study of humans and every aspect that affect our lives in the past and present times.
From studying the garbage heaps, we could see the type of things that humans use in their day to day life, from food, cosmetics, type of newspaper that they read, type of technology that they use, etc.