to protect itself from predators
Grass.
Yes . They blend in with the rocks and water .
Their shells look like their environment. They blend in by hiding in their shells.
If you mean to defend or protect itself they blend in with the grass so they're not seen
the answer to that is by vibration. in the wind.
it helps the animal blend in to its environment
It helps them blend into their environment.
Due to their body structure
They blend in with twigs and branches.
Sort of. They cannot change their skin colour but their color is good camouflage for hiding in grass and on leaves
An animal's ability to blend with its environment is called protective camouflage. However, if you are not looking for camouflage as an answer, this ability is also called crypsis.
The word you are looking for is "assimilate." It means to blend in or adapt to a new environment or culture.