(Source:http://www.google.co.in/search?um=1&hl=en&biw=1350&bih=634&noj=1&tbm=isch&sa=
1&q=animal+limbs&oq=Animal+limbs&gs_l=img.1.0.0j0i5i24.111370.119700.0.122047.12.11.0.1.
1.0.843.2785.3j4j1j0j2j0j1.11.0...0.0...1c.1.zEWzqBo-6iA ; Oct. 17, 2012)

The limbs of animal (plate 7A &&B) serve various activities based on purposes. Imagine how we may operate without our limbs? Usually human limbs demonstrate climbing, hugging, kicking, jumping, swimming, running activities. Each time the limbs act differently. Without the joints of shoulders, elbows, wrist, hips, knees, and ankles, we can make no movements. We extend or retract our size in different situation with the help of arms and legs along with other part of the body.

Plate 8A Functioning Fish Parts	8B Joints of Fingers

(Source8A:http://www.google.co.in/imgres?start=114&num=10&hl=en&biw=1350&bih=602&tbm=isch
&tbnid=LbsO7e49ueR1jM:&imgrefurl=http://www.calacademy.org/teachers/resources/lessons
/fishprints/&docid=_0UXYBbnz34wvM&imgurl=http://www.calacademy.org/teachers/upload/docs/fish
anatomy289x203.jpg&w=289&h=203&ei=sZ9_UMiPGYzrAe15IGYCQ&zoom=1&iact=hc&vpx=666&
vpy=174&dur=5794&hovh=162&hovw=231&tx=161&ty=81&sig=107558784989213064148&page=7&
tbnh=145&tbnw=207&ndsp=21&ved=1t:429,r:16,s:100,i:52 ; Oct. 18, 2012

Similarly other living being use their limbs for various purposes.  The gestures of limbs can signify powerful meaning as non-verbal communication. Fish (plate 8A) is equipped with various parts for the movement and defence system. The finger and other limbs (plate 8C) have complex joints allow various functioning in wide range of orientations.