Question

the theory of plate tectonics states that the outer layer of earth is divided into large, rigid blocks called plates. what could happen that may lead to a change in this theory?
scientists discover new information about earths layers.
scientists begin observing earths outer layer.
scientists update their opinion of the theory.
scientists revise the definition of theory so that it fits with what they believe.

Explanation:

Scientific theories are based on evidence. If new information (like about Earth's layers) is discovered, it can lead to a change in the theory. Observing the outer layer (already done for plate tectonics theory), updating opinion without new evidence, or revising the definition of theory to fit belief (not based on evidence) are not valid reasons for changing a scientific theory.

Answer:

Scientists discover new information about Earth's layers.