Hi!

DNA is the polymer of which each chromosome is made, so the question "how many DNA does a single chromosome contain?" makes no sense unless you mean how long is the DNA sequence of each chromosome. The chromosomes have various lengths and sequences, so yes, the entire genome of a human being is made up of the sequences of all the chromosomes together.

Thanks a lot sir

Each chromosome contains one single molecule of DNA. So, in total, there are 46 DNA molecules in human chromosomes. The human nuclear genome is a combination of all 46 DNA molecules which is ~3.2 billion base pairs.

 Thanks a lot madam for the beautiful and lucid explanation.