Two
3
They're the same thing, but there are many kinds of them.
yes
Yes.
Pillbug
Crabs have six segments. Segments are how many parts of the crab they have.
there are infinitely many segments in a line.
It falls under Isopoda -- "Shelled" crustaceans with 7 pairs of legs.
arachnida has 15 segments
5 line segments
Harvestman have 3 body segments