On the American lobster you might be familiar with, that has the large front claws (not the spiny lobster with the giant antenna but tiny claws) there is a larger claw and a smaller one. The bigger one is for crushing prey and has rounded bumps; the smaller is a cutter and has sharp inside edges used for holding and tearing prey.
Lobsters don't have tentacles :P But they do have five pairs of legs.
Isopods are crustaceans, as are lobsters. Crustaceans are a class in the phylum Arthropoda. Fish, however, are a class in the phylum Chordata, or vertebrates. So, not related to isopods, or lobsters. ^^
The primary defensive feature in lobsters would be their behavior - avoidance of predators; they hide in crags or bury themselves in silt, or otherwise hide. This is especially important after they shed. A mottling or other coloration effects help. When confronted, they can use their claws to attack, or implement a flight reflex called the caridoid escape reaction by compressing their tail (abdomen) to swim backwards. There are also social defence behaviors, where they can group to increase mutual safety.
Lobsters are not fish. Fish are part of the phylum Chordata, along with other backboned animals (amphibians, reptiles, birds and mammals), and lobsters are arthropods (phylum Arthropoda :P), having no backbone and being completely unrelated (very much related to insects in fact). Lobsters have ten jointed legs and a hard carapace.
Lobsters
yes. all lobsters have claws
Chelipeds are the main grasping claws of crustaceans. The two biggest claws on lobsters, crabs etc.
None. Lobsters do not HAVE wings. They have two claws.
Because the claws got cut of
yes they are
Exoskeletons and claws, but lobsters have ten legs while crabs have eight.
its claws and shell
its claws and hard plates on its back.
with it's sting and claws!
lobsters protect themselves by hiding in holes at the bottom of the ocean of they use there claws.
Yes, lobsters regrow legs, claws and antennae, but can not regrow their tails.
Yes, that is what those huge claws are for.