Question

question 1 - 1
why are scientific theories rarely discarded completely?
once published, scientific theories cannot be revised
they only change when the opinions of famous scientists change
they are based on reliable evidence that is difficult to disprove entirely
scientists do not continue testing theories after they have been discovered

Explanation:

Scientific theories are developed based on extensive research and evidence. They are not just guesses but are built on a foundation of reliable data. Even if new evidence emerges, it usually leads to refinement rather than complete discard. For example, the theory of evolution has been updated over time as new fossils and genetic evidence were found, but the core idea remains. The option "They are based on reliable evidence that is difficult to disprove entirely" aligns with this concept.
The first option is wrong because scientific theories are constantly revised. The second option is incorrect as scientific theories change based on evidence, not just the opinions of famous scientists. The fourth option is false since scientists do continue to test theories even after they are proposed.

Answer:

They are based on reliable evidence that is difficult to disprove entirely.