Which electronegative element/compound do chemosynthetic bacteria use drive the electron transport chain

Which is an example of a vestigial structure? a: paw of a lionb: wing of a birdc: appendix of a humand: tail of a cat(i think it's a but i'm not sure)

Male-patterned baldness is more common in males as the name suggest.why is this? a.the gene for baldness is on chromosome 5 b.the gene for baldness is on chromosome 1 c.the gene for baldness is on he x chromosome d.the gene for baldness is on the y chromosome

What evidence for the age of the earth is indicated by the fact that sedimentary rock is found on mountain tops? that the earth has expanded outward from water beds that mountains formed first before anything else that some force lifted the rocks from the water the earth is not very old and has not had time for many rock layers to form