RTK Query, createSlice vs createReducer

[codingPerson2]

Hello I am totally new in the redux toolkit options. So I want to know some things.

1. RTK Query is using redux store for storing the data right ?
2. Can I use immer extension from ReduxToolkit in the transformResponse property ?
3. Does the RTK Query replace the process of fetching data using Redux Thunk, actions, stores and reducers ?
4. When should I use createSlice, when createReducer and when RTKQuery?
5. Is the some built in option for the promise.all feature?