Answer:
The field of study that Veronica is exploring is geology.
Step-by-step explanation:
Geology is part of the geographic sciences, more specifically being part of the physical geography. It is the science that examines the origin, history, structure, and composition of Earth. This gives this science a very wide dimension for exploration, so it very often is found collaborating with other sciences.
The rivers, with their power, manage to break the rocks into small particles and carry them to another location. How big will the particles be, depends on the characterisitcs of the river, but also on the characterisitcs of the rocks. Further examination of the size of the particles that a river is depositing and the effects of it goes directly into the geology sphere, as the rocks as such, their erosion, and their deposition and later formation of new rocks, are one of the biggest interest of this science.