Final answer:
Chromosomes are the most highly condensed form of chromatin. They are formed during mitosis and are the highest order of chromatin structure seen in metaphase. During interphase, chromatin exists in different forms called heterochromatin and euchromatin.
Step-by-step explanation:
The most highly condensed form of chromatin is chromosomes. Chromosomes are formed during mitosis when chromatin is maximally condensed.
During interphase, chromatin exists in different forms called heterochromatin and euchromatin, with euchromatin being more dispersed and accessible for replication and transcription. Chromosomes are the highest order, most condensed form of chromatin seen in metaphase of mitosis.