There are a lot of topics one could potentially learn about by studying Biological and Life Sciences. The field involves the study of nature and its phenomena, whether one is interested in medicine or sustainability, they will find something in this field.

The PhD is a doctoral degree, specifically called a "doctor of philosophy" degree. This is misleading because PhD holders are not necessarily philosophers (unless they earned their degree in philosophy!). That said, PhD recipients are able to engage in thought experiments, reason about problems, and solve problems in sophisticated ways.