The bond between the phosphate and hydroxyl group of sugar is ...........

Identify the correct matching for Euchromatin and Heterochromatin from the given statements:
$I -$ Loosely packed
$II -$ Densely packed
$III -$ Darkly stained region
$IV -$ Lightly stained region
$V -$ Transcriptionally active chromatin
$VI -$ Transcriptionally inactive chromatin
Euchromatin $\quad\quad$ Heterochromatin

The octamer that forms a complex unit with $DNA$ is called:

The $DNA$-histone complex can be removed from chromosomes by treatment with:

The Feulgen reaction is specific for:

What is the full form of $DNA$?