How is possible that those shapes are equivalent in topology?

I recently started to study topology, I have no idea about the subject so my question could be very simple but I need a clear explanation. It is about the page number 19 of Introducton to Topology by Colin Adams and Robert Franzosa; it said that the shapes:

donut

sphere with two holes

are equivalent in topology, but one has just one hole and the other has two. is possible to add holes or stick holes?


Solution 1:

Look a bit more closely at the second picture. There's a couple of little dotted lines connecting the two holes that may be a bit hard to see.

(left pic is from post, right pic is super contrast enhanced to tease out line)

That is meant to convey the impression they are the two ends of a single, long, curved hole through the interior.

Solution 2:

The "two holes" in that sphere are two ends of the same hole. (That is, if you drilled one hole all the way through a sphere, you would end up with something that looked very much like your picture.)