Answer:
The long strands of double-helical DNA wrap around histone proteins. The wrapping goes on and on to achieve the secondary and tertiary level of packing. In the end, the whole thing is highly packed enough to fit inside the nucleus of a single cell.
Explanation:
Just to add on over time they have develiped a tuff outer layer to stop weather and insects from harming them.
Layer 10 is were you most likely find coal