Explanation

Box 1: No
Box 2: Yes
ContinueOnError: When true, continue processing the next request in the collection even if a fault has been returned from processing the current request in the collection. When false, do not continue processing the next request.
ReturnResponses: When true, return responses from each message request processed. When false, do not return responses.
When false, the Responses collection will not be empty if errors are returned. If errors are returned, there will be one response item in the collection for each processed request that returned a fault and Fault will be set to the actual fault that occurred.
Box 3: No
Box 4: Yes
For example, in a request collection that contains six requests where the third and fifth request return faults, the following table indicates what the Responses collection would contain.
ContinueOnError=true, ReturnResponses=false: 2 response items: 2 have Fault set to a value.
Reference:
https://docs.microsoft.com/en-us/powerapps/developer/common-data-service/org-service/execute-multiple-reque