What are the differences between B trees and B+ trees?

Question

In a b-tree you can store both keys and data in the internal and leaf nodes, but in a b+ tree you have to store the data in the

Answer 1

In B+ Tree, since only pointers are stored in the internal nodes, their size becomes significantly smaller than the internal nodes of B tree (which store both data+key). Hence, the indexes of the B+ tree can be fetched from the external storage in a single disk read, processed to find the location of the target. If it has been a B tree, a disk read is required for each and every decision making process. Hope I made my point clear! :)