Multiple choice: why have none of the competing hypotheses about the origin of life on earth been developed into a scientific theory?
another conflicting hypothesis that holds the answer has yet to be stated.
the hypotheses only disagree in whether self-replicating material was dna or rna.
these particular hypotheses are not testable.
the results of experimentation often yield conflicting data.

18. determine whether each stateme blank space given. ach statement is true (t) or false (f). place your answer in the 8. when a cell is put into an isotonic solution, individual wat put into an isotonic solution, individual water molecules cannot move back and forth across the cell membrane. d. when a cell is put into a hypertonic solution, there is a net movement of water molecules across the cell membrane into the cell. c. when a cell is put into a hypotonic solution, there is a net movement of water molecules across the cell membrane out of the cell. d. the movement of any solvent across a semi-permeable membrane is called osmosis. e. carrier proteins have the ability to change shape and physically move molecules across the cell membrane. f. in facilitated diffusion, the concentration of the molecules to be moved across the cell membrane is higher inside the cell.