How are insects different from spiders and centipedes?

For insects, they have three pairs of legs or six legs. On the other hand, spiders have four pairs or eight legs. Spiders and insects also have a difference when it comes to their major body parts. Spiders only have two main body parts while insects have three main body parts.

the reason the two sea urchins don't compete with each other for food, resources, etc. is because the urchins have adapted to the environment but they have also adapted to each other. this is most likely because the genes of the sea urchins.

if you add everything up correctly you should get 69 i got this because 50 plus 19 is it