Answer:
Centimeter (cm)
Step-by-step explanation:
A student performs an experiment and must measure the lengths of four different objects: a textbook, a pencil, a cup, and a piece of bread.
There are so many units of measuring length of an object like centimeter, millimeter, kilometer etc. Some of units are used to measure very large distances (i.e. the distance between sun and earth etc ) are light year, astronomical units etc.
In this case, a textbook, a pencil, a cup, and a piece of bread are small object. The most appropriate unit of measurement for her to use is centimeter or cm.