During what phase(s) of mitosis does a chromosome consist of 2 chromatids? Of one chromatid?

mitosis-chromosome
chromatids

#1

during what phase(s) of mitosis does a chromosome consist of 2 chromatids? Of one chromatid?

Answer:

Prometaphase (after prophase and before Metaphase).
In prometaphase, single chromatids become two but they are attached and in metaphase they will align to form the metaphase plate.