A theory
1. may be revised or replaced.
2. is always true.
3. is the opening statement of an experiment.
4.is a problem to be solved.
1. may be revised or replaced - This statement is correct. Theories are not set in stone and are subject to revision or even replacement as new evidence or information emerges.
2. is always true - This statement is incorrect. Theories are not "always true" as they are based on the available evidence and may be modified or disproven as new evidence emerges.
3. is the opening statement of an experiment - This statement is incorrect. Theories are broader than individual experiments and are explanations or frameworks that are developed to explain observed phenomena. An experiment is conducted to test the predictions or implications of a theory.
4. is a problem to be solved - This statement is incorrect. Theories are not problems to be solved but are explanations or frameworks that attempt to explain observed phenomena. Problems or questions arise when there is a gap in understanding or when a theory is inconsistent with the available evidence. Theories can offer potential solutions or explanations to these problems, but they are not problems themselves.
The correct answer is:
1. A theory may be revised or replaced.
Explanation: A theory is a well-substantiated explanation of certain phenomena based on observation, experimentation, and evidence. It is not considered as an absolute truth because new evidence or advancements in scientific knowledge may lead to the revision or replacement of a theory. Scientific theories are continually refined and modified to account for new findings and improve our understanding of the natural world.