I want to know the answer to the following question:
What is the lowest altitude where acclimatization or a suit is not needed to prevent sickness in humans?
All the background I'm provided with is that "Above this altitude, oxygen enrichment is necessary to prevent altitude sickness in humans that did not undergo prior acclimatization, and spacesuits are necessary to prevent ebullism above 19 km.". Is that enough to answer the question?
Answer: no