Because double bonds cause the hydrocarbon chain to bend. Therefore, the fatty acids cannot compact tightly together, reducing the van der Waals interaction between the fatty acids. The melting point of fatty acids is also affected by chain length. The longer the hydrocarbon chain is, the higher the melting point.
The systemic lupus erythematosus (SLE) is an autoimmune disorder that may be linked to both environmental and genetic factors. This disease is caused by the own immune system (i.e., antibodies) that is directed against the body's tissues in a healthy person.
you are using your shoulder muscle. The reason you are using this muscle is when you put your arm strait up there is no reason to use a bicep or tricep muscle.
