Answer:
The type of food Bob is given.
Explanation:
An independent variable in an experiment is the variable that is changed. Here, the type of food is the only thing that is changed and the amount of water, temperature and other variables were kept constant (same). Thus, the independent variable is the type of food Bob is given.
I think the answer is C) R I had this question and that was right for me hope this helps!
Answer;
-Pellicle
Explanation;
-Protist cells may contain a single nucleus or many nuclei; they range in size from microscopic to thousands of meters in area. Protists may have animal-like cell membranes, plant-like cell walls, or may be covered by a pellicle.
-On a paramecium's exterior is found the pellicle. The pellicle is stiff to maintain the paramecium's shape and provide stability but it is also flexible to allow movement. It also acts as an attachment site for external organelles such as cilia.