Final answer:
Some rectangles have adjacent sides that are perpendicular, but not all.
Step-by-step explanation:
The statement that is true for some, but not all, rectangles is option H: Adjacent sides are perpendicular. This means that while some rectangles have adjacent sides that are perpendicular, it is not a property that applies to all rectangles. Rectangles only have perpendicular adjacent sides if their angles are right angles.
For example, consider a rectangle where the length is 4 units and the width is 3 units. The adjacent sides of this rectangle are indeed perpendicular, forming right angles.
Therefore, option H is the correct choice as it adequately represents the property that applies to some, but not all, rectangles.
Learn more about properties of rectangles