1 Muscle weakness and Pain in the joints and Sudden onset of joint pain and Arthritis-like symptoms (3 causes) 2  Muscle weakness and Pain in the joints and Sudden onset of joint pain and Body symptoms (3 causes)  Muscle weakness and Pain in the joints and Sudden onset of joint pain and Bony abnormalities (3 causes)
The other two chromosomes, X and Y, are the sex chromosomes. This picture of the human chromosomes lined up in pairs is called a karyotype. In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46.
Here is the way I think about it: before S phase, a typical human cell contains 46 chromosomes. During S phase, all 46 chromosomes are replicated. Because they are identical copies, it is perfectly fine to say that there are now 92 (46 + 46) chromosomes in the cell.