Here is my first question: As we all know that, fat and oil(lipid) are triglycerides, they differ in the hydrocarbon tail with fat(saturated fat) without C=C, whereas lipid(unsaturated fat) having C=C in the hydrocarbon tail. My question is why does having a C=C will lower the metling point? And how how about their boiling points? My second question is why does the rate of transmission of nerve impulses is faster if the diameter of the axon is larger? My text book says larger diameter of the axon reduces the resistance offered by the axoplasm within; does this mean that larger diameter, the axoplasm density is lower? Thank you!