Which concept asserts that quantity remains constant when shapes change?

• A. Volume remains constant when shapes change
• B. Quantity changes with shape changes
• C. Object Permanence
• D. Conservation

Answer: (D)

Conservation is the understanding that the amount of something stays the same even when its shape or arrangement changes. If you roll a lump of clay into a ball or flatten it into a pancake, the amount of clay is the same even though the shape looks different. The same idea applies when you pour liquid from a tall, thin glass into a short, wide one—the volume is preserved even though the appearance changes. This broader, invariant principle is exactly what the statement about quantity remaining constant when shapes change expresses, making it the best answer. The other options don’t fit: claiming volume remains constant is too specific to one type of quantity; object permanence is about whether objects continue to exist when not seen; and saying quantity changes with shape changes contradicts the fundamental idea of conservation.