I am in the middle of a physics experiment that has recently crossed over into biology...the details are not important, but what i found was that a certain property changed in this order as the following substances were scanned: 1. muscle 2. liver 3. fat 4. heart 5. cartilage 6. bone marrow is there any biological or physical property (density, protein content, etc??) that would change in that order? e.g. does muscle have the least protein content and bone marrow the most? or vice versa? or is it maybe the size of the molecules that vary in that order?