An organ system is made up of A.
organs that work together to perform a certain function.
B.
organisms that have similar behaviors and appearances.
C.
all of the tissues found in an individual organism.
D.
identical cells that perform the same function.

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