Describe the structure of a chromosome

The chromosome's physical appearance is like the controller of a marionette (The wooden x). A chromosome has 2 identical chromadits, each chromadit contains 1 DNA molecule. The chromosome has 2 arms, p arm and q arm. The P Arm is the shorter arm and the Q Arm is the longer arm. The point where the chromosome is constricted is called a centromere. 

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Ithink it is called reservation