a controlled single-variable laboratory test support through evidence from numerous observations proposal of alternative explanations with predictive value a full-scale replication of each event in the proper sequence
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: The hypothesis of an expanding universe required which type of validation before being accepted as a significant part of scientific theory?
Possibilities:
- a controlled single-variable laboratory test
- support through evidence from numerous observations
- proposal of alternative explanations with predictive value
- a full-scale replication of each event in the proper sequence

support through evidence from numerous observations