The right answer is Joints (or ligaments more precisely).
Muscle is the contractile structure that produces strength. It has components that allow it to be shortened to create what is called a muscle contraction.
The joint is junction of two parts of the skeleton allowing them relative mobility.
The ligament is an elastic structure that stabilizes the joints. It therefore attaches from one bone to another.
Nondisjunction is defined as the failure of the chromosomes to seperate during cell division. An animal with a haploid number of 6 (diploid number of 12) undergoes meiosis, and at the meiosis II (cells are already haploid from the meiosis I), nondisjunction occurs. The mature ovum will contain 6+1 chromosomes (n+1) because there is an extra chromosome from the nondisjunction. The second polar body will contain 5 chromosomes (normal would be 6) because the second polar body did not receive that extra chromosome due to nondisjunction. In the event of fertilization of the abnormal ovum with a normal sperm, the zygote will be a diploid (12 chromosomes) normally but since the ovum as an extra chromosome from the nondisjunction then the zygote will have an extra chromosome (13 chromosomes). One pair of chromosomes has an extra single chromosome and this is called a trisomy.
I think you should go to a chiropractic or tell somebody or go to the doctor if ur young I suggest telling your parents