A harmful substance. A. Pollution B. Overharvesting C. Runoff water D. Exotic species

Sediment layers stop lateral spreading when: they encounter a barrier they encounter an opposing current they run out of additional sedimentary material

Most of the carbon on earth is stored in the form of

According to theories of how life began, how did early organic molecules begin to separate from the outside world? a: specialized enzymes were required b: chains of amino acids created a barrier c: formation of microspheres or vesicles d: rna catalyzed the formation of membranes