1. I would say that a limiting nutrient is anything that is necessary for growth, but which can cause problems if there is an excess. For example, phosphorus is necessary for plants to grow, but too much can probably lead to problems. It is normal for a lake like Lake Erie to have phosphorus in the water, but since there is too much, the algae is growing out of control. Phosphorus is a “limiting nutrient” because it is only required in small amounts for proper growth and balance in the ecosystem.

2. The statement is an observation because it describes something that is happening and it does not try to explain the cause of the algae, the way a hypothesis would. A hypothesis would say something like: the increase in algae in the Great Lakes