Question 1 :
With failure transparency, all of the actions of a transaction are committed or none of them are committed.
Question 2 :
Each site (or node) in a distributed system is subject to the same types of failure as in a centralized system.
Question 3 :
Replication may use either synchronous or asynchronous distributed database technologies, although asynchronous technologies are more typical in a replicated environment.
Question 4 :
Synchronization for pull replication is less disruptive and occurs only when needed by each site, not when a central master site thinks it is best to update.
Question 5 :
With asynchronous technology, if any copy of a data item is updated anywhere on the network, the same update is immediately applied to all other copies or it is aborted.