Answer:
A Chromosome is a long thread-like structure that are known to form the DNA molecule, and chromatid is one half of two identical copy of DNA. The two chromatids are joined together to form the chromosome. And chromatids are made up of a substance called as chromatin.
Chromosomes and chromatids are closely related to each other and both of them are made up of DNA molecules. Chromosomes carry the genetic material and chromatids form the DNA.