Answer:
The dependent variable is the number of clams developing from fertilized eggs.
The independent variable is the water temperature
The optimum temperature for clam development is 30 degrees centigrade.
Explanation:
The graph of the number of clams developing from fertilized eggs and water temperature is attached to this answer.
The independent variable is being manipulated in an experiment. As it changes, it produces a corresponding change in the dependent variable.
Here, the water temperature is the independent variable. As it changes, the number of clams developing from fertilized eggs (dependent variable) also changes alongside.
The optimum temperature is the temperature at which the greatest number of clams developing from fertilized eggs is produced. We can see from the graph that this temperature is 30 degrees centigrade.