The most common site are the skin overlying the sacrum, coccyx, heels or the hips, but other site such as the elbows,knees, ankles or the back of the cranium can be affected.
I believe the correct answer would be actin filaments. These are polmers that are linear with G-actin as subunits that attaches ith myosin heads during the skeletal muscle contraction. They are necessary for cell shape, adhesion and contraction.
Because it is for school related topics. Join a chat room that allows you to say as you wish. Like your mom would say: Their house, Their rules.