What effects do keystone specie shave on an ecosystem?
A. They make prey species extinct
B. They reproduce biodiversity
C. They keep populations of species balanced
D. They cause primary disturbances.

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