Answer: Mouth.
Explanation:
The mouth is known to be performing both the tasks of chemical digestion and mechanical digestion.
The food is ingested through mouth and the teeth perform the process of mechanical digestion by breaking down the food particles into smaller particles.
Then the saliva gets mixed into the food and the enzymes(amylase) present in the saliva helps in the digestion of carbohydrates.
So, mouth is the organ that performs the process of both mechanical and chemical digestion.
Albert, a student researcher, varies the amount of food given to rats in an experiment to measure the effect on their learning behavior. In albert's study, the amount of food given is the independent variable.
An independent variable is under the control of the experimenter. Independent variable does not depend on the other variables involved in the experiment. Since the amount of food is varied, it is not depending on other variables like size of mice, weight, etc.
B. Gene. Piebalding is caused by mutant copies of genes.
