Challenge 1: Preparing a Plain Cylinder to Bend Only Its Middle Section — Solution Walkthrough

The answer:

Per this chapter's own material, adding loop cuts to the cylinder's
middle area is the necessary preparation step. A loop cut adds a new
ring of edges running around the existing mesh, subdividing that
section into more, smaller faces without changing its overall shape.

Why a plain, unsubdivided cylinder can't be bent locally as-is:

Without additional edge loops in the middle section, the cylinder's
own top and bottom edges are the only real geometry available to
manipulate — there's nothing separating the middle from the rest of
the shape, so any bend applied would have to affect the whole cylinder
at once rather than just its middle section.

Why loop cuts specifically solve this:

Per this chapter's own material, loop cuts are described as essential
preparation for exactly this kind of localized edit — enough
additional geometry needs to already exist in the area being bent so
there's something there to actually bend around, separate from the
untouched top and bottom.

WHY THIS WORKS AS AN ANSWER
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This exercise checks that a localized bend is correctly recognized as
requiring loop cuts as a preparation step, rather than being
achievable directly on unsubdivided geometry.