What are two characteristics that animals classified as vertebrates might share?
what are two characteristics that invertebrates might share?

Vertebrates:
1) They've got a backbone/spine.
2) Are probably more complex organisms: fish, amphibians, reptiles, birds, mammals (in that order.)
3) Movement is based on an internal skeleton.
4) Wide range of sizes and shapes.
5) K-selected population

Invertebrates:
1) No backbone.
2) Less complex: sponges, worms, mollusks (e.g. snails) , crustaceans (e.i. crabs.) Insects.
3) Movement is not based on an internal skeleton, or some don't move at all.
4) Must be small in size to fulfill their needs for air and nutrients because systems are simpler.
5) R-selected population

The answer is ozone layer.

Yes he thought they should be left to chance why, because he thought that was the best thing to do