What do we call the process by which harmful toxins become more and more concentrated in organisms in a food chain

Bioaccumulation. I hope this helps you out :D

lizards have adapted to life in the desert. some desert lizards have toes with spiny scales to them run across the sand without sinking. some use the sand to hide from predators, or to search for small animals that they prey upon.

not sure if this what   you'r looking for would be percent composition