Q. What are the euchromatin and heterochromatin?

Chromatin is uncondensed nuclear the DNA the typical DNA morphology in interphase the phase of the cell cycle in which the cells is not separating itself. In this phase of the cell cycle chromatin can be found as heterochromatin, further more condensed and dark (in electronic microscopy) portions of the DNA molecules, and as euchromatin, less condensed and lighter portions of the DNA molecules.

Since it is uncondensed the euchromatin is the biologically active portion of the DNA that is the region that has active genes to be transcripted into the RNA The heterochromatin represents the inactive portions of the DNA molecule.