Which of the following descriptions of the DNA double helix structure model is true ？
选项：

A:The composition of DNA bases in different tissues of the same organism is very similar.
B:The base pairs in the DNA double helix are on the inside
C:Two polynucleotide chains are connected by a hydrogen bond between A-G and C-T
D:The main factors maintaining the stability of the double helix are hydrogen bonds and base stacking forces