Clam shells are quite durable.
A clam.
A clam is more likely. Jellies have no bones.
A clam is more likely to fossilize than a jellyfish.
Because it is more resistant to biological and environmental destruction.
Jellies have no bones. When they die, they just dissolve.
A mammoth is more likely to fossilize than a caterpillar because a caterpillar has no hard tissue. Bones and cartilage are much more likely to fossilize.
Bones typically fossilize the most. There are some examples of fossilized feathers and hair, but it's rare.
Teeth are the most likely part of a dinosaur to fossilize, because they are hard and dinosaurs lost and replaced them many times over their lifespans. Next are bones, especially large bones, horns, and claws.
snail
A fox would be the most likely. A moth is smaller, and therefore would take less time to decompose. However, for anything to(technically) fossilize takes a very long time
Not everything will fossilize because not everything is under the right environment to do so. Animals must die in a wet place in order to fossilize.
Sand is porous, so air get get through it, but mud can keep air out.