Question

shrinkage and warping
use the information below to answer the question.
shrinkage and warping can happen to prints done with a heat process or a resin
process when curing.
causes
in a process that uses heat, such as fused filament fabrication (fff), there can be a
heat gradient that causes the material to bend. this can continue with each layer. this
is caused by the shrinkage from the differential in heat as each layer is laid down.
the other cause of warping is due to differential curing, which has nothing to do with
heat. in a process such as sla, the material will shrink somewhat from the layer above
it, which can cause it to warp.
prevention strategies
controlling the atmosphere or ambient heat will help prevent warping. keep the
environment as consistent as possible. having an enclosure is a good way to do
that. support structure helps prevent warping due to shrinkage as well. having the
print anchored to the bed will reduce the likelihood of warping.
design techniques can also help prevent warping. keep a uniform wall thickness
throughout whenever possible. avoid long, flat pieces. breaking up the surface into
two (or more) pieces, if possible, will reduce the chance of warping.
in a printing process that uses heat, what can cause the
material to bend?
the build plate
support structure weight
balance inconsistencies
a heat gradient

Explanation:

The text clearly states that in a heat - using process like Fused Filament Fabrication (FFF), a heat gradient causes the material to bend. This is the key information provided in the "Causes" section for heat - based processes.

Answer:

a heat gradient