Gregory should speak with a physiologist. Here's why:
1. Physiologists study the life processes of living organisms, including plants. They focus on how plants function at a cellular or molecular level, how they grow, reproduce, and respond to their environment.
2. A bioengineer typically focuses on applying engineering principles to biological systems, which might not align directly with Gregory's interest in studying the life processes of plants.
In this case, a physiologist would be the most suitable biotechnology R&D professional for Gregory to speak with regarding his interest in working with plants.