Sql Baseline queries

Q1. If a baseline is Enabled, Accepted but not Fixed will the optimiser swap to a better plan if it generates ones ?

Q2. If a baseline is Enabled, Accepted and Fixed will the optimiser swap to a better plan if it generates one ?

Q3. So what happens if you have Fixed and Adaptive set ? Will the optimiser generate and change to a better plan if it can create one ?

Q4. So the purpose of a baseline is to guarantee no degradation in performance, to guarantee a minimum level of performance but how does it guarantee this if the baseline is dependent on the underlying components eg indexes, fresh stats etc?