Answer:
The eroded rock and soil materials that are transported downstream by a river are called its load. A river transports, or carries, its load in three different ways: in solution, in suspension, and in its bed load. Mineral matter that has been dissolved from bedrock is carried in solution.
Explanation:
The main reason is because they are heavy, and because they don't have to chase their food. They're not predators and their shells give them protection like running away gives protection to other herbivores.
Answer:
the answer might be the number 2