Answer:
The independent variable in Part I, the one that is intentionally manipulated, is the
✔ type of material
.
The independent variable in Part II, the one that is intentionally manipulated, is the
✔ charge of an object
.
The independent variable in Part III, the one that is intentionally manipulated, is the
✔ movement of a magnet
.
The independent variable in Part IV, the one that is intentionally manipulated, is the
✔ presence of an electric field
.
Explanation:
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