In hetrochromatin genes cant be expressed it it true!?

Yes, that is generally true. Heterochromatin is a tightly packed form of DNA that is not actively transcribed or expressed. This is because the genes within heterochromatin are inaccessible to the transcription machinery, preventing their expression. In contrast, euchromatin is a more loosely packed form of DNA that is accessible to transcription factors and allows for gene expression.

True