Acommon dna structural feature involved in gene regulatory systems is
a. supercoiling of dna.
b. looping of the dna.
c. unwinding of the double helix.
d. coiling into z-dna.
e. double-strand breakage of dna

enhanced global partnerships and exploration capabilities may advance international preparedness for protecting the earth from catastrophic events such as some asteroid strikes, advancing collaborative research on space weather and protecting spacecraft by developing new means for space debris removal.

"a.) well–developed vascular system."