many questions about App Store Server API

Hello, I have a few questions about the App Store Server API.

1. According to the document, if 'OriginalTransactionIdNotFoundError(errorCode: 4040005)' is received as a response after calling the production environment API if there is no environment information, it is written to call the sandbox environment, but 'Get Transaction Info' / 'Get Transaction History' API call and when 'TransactionIdNotFoundError(errorCode: 4040010)' is received, can I call it in the sandbox environment?

2. Is the root certificate of the X.509 certificate chain on x5c claim in JWSDecodedHeader always AppleRootCA-G3?

3. If I add and recall the query parameter '?sort=DESCENDING' in the Get Transaction History API, will the first transaction information always have the largest expiration date?