There is nothing different
Spider.
Lobsters are saltwater and crayfish (crawdads) are freshwater.
the grasshopper is more closely related to the housefly.
it isn't
The plural of "crayfish" can be either "crayfish" or "crayfishes." Both forms are accepted, with "crayfish" being more commonly used. The term refers to multiple individuals of the same species, similar to how the word "fish" can refer to multiple fish of the same or different species.
They are both invertebrates.
They are shellfish, they have an exoskeleton.
A uropod is used for swimming. Telson does the same thing.
I am not sure, but from what I can conclude from diagrams and from a recent dissection no, the crayfish does not have a liver. Although you should consider asking your biology teacher just to be sure.
A crayfish is a crustacean that has a similar appearance to the shrimp. When referring to a group of crayfish you simply call them by the same name.
Spider, crayfish, grasshopper, tick, and butterfly all belong to the phylum Arthropoda, which is characterized by exoskeletons, segmented bodies, and jointed appendages. Specifically, spiders are part of the class Arachnida, crayfish belong to the class Malacostraca within the subphylum Crustacea, grasshoppers and butterflies are part of the class Insecta, with grasshoppers in the order Orthoptera and butterflies in the order Lepidoptera. Ticks, like spiders, are also classified under Arachnida.
It's impossible to be bitten by the same spider that Peter Parker was bitten with because that spider was not a real kind of spider.