What is Backlog about Scrum?
Backlog is a list of what has to be done. I'm referring to the definition without relating to Scrum.
What is Product Backlog?
Product Backlog is a list of things to do to build a product. This list is maintained by Product Owner and is the basis for prioritizing iteration schedules, or sprints .
What is Sprint Backlog?
Since Product Backlog items are prioritized, the Sprint Backlog is generated and then the team should focus on those requirements during this iteration.
What is the Backlog's influence in relation to a project where it is
using Scrum?
The Backlog influences the flow of activities and priorities that the team must meet as this should be aligned with the client's needs in all sprints.