is rebase the same as merging every commit?

Rebasing is described in the docs I've read as turning this: (sorry for the dots)

..........A---B---C topic ........./ ....D---E---F---G master

Into this:

...................A'--B'--C' topic ................../ .....D---E---F---G master

If I understand it right (and that's a BIG if), it's the same as doing a merge of C into G where every individual commit in the C-line is individually committed into the new C' line.

...........-------------A---B---C ........../ / / / ........./ /---A'--B'--C' topic ......../ / ....D---E---F---G - master

(1) Is the above model a valid explanation?

(2) From the documentation diagrams, it looks like the rebased A' has only (G) as a parent, not (A,G). If this is the case, why? (i.e. not connecting those nodes throws away useful information)

(3) If it only has (G) as a parent, does the rebase explicitly remove the source A,B,C nodes from the repository? (the diagrams make it look like it does) ..or do they just get cleaned up during GC?