Normal faults can occur in pairs creating surface features called horses and grabens. grabens are the dipped formations which are hanging wall blocks that have dropped relative to their footwalls. the raised footwall blocks are the horsts. here is a cross section of rock strata where pairs of normal faults produce horsts and grabens

answer; both surfaces of the membrane are nonpermeable

in addition to being able to metabolize, grow, digest food, and excrete wastes, what other functions must an organism perform if it is to survive? survival also depends on the ability to maintain one's boundaries, to move, to respond to stimuli, and to reproduce. oxygen is a survival need.