Answer:
A
Explanation:
Because there are two DNA strands in the DNA molecule and they both rotate around each other in a helix formation. So two helixes = double helix.
<span>I suspect this question should read "How long does a red blood
cell live." A red blood cell lives for between 100 and 120 days. It
takes 7 days for a new red blood cell to develop from stem cells. Stem
cells are similar to base cells. They can also be seen as a general
template from which specialized cells are made. Stem cells can be taken
from a newborn baby's umbilical chord or extracted from an adult blood
donor's blood.</span>
Answer: the capillaries.
<span>The blood capillaries are blood vessels with very small caliber. They form the blood distribution and collection network in cells. They are the communication between branches
originating from the arteries and with the smaller
veins. It is on the walls of the capillaries that occurs <span>the exchange of water, oxygen, CO2,
other nutrients and chemical residues.</span></span>
The horsehoe crab because it was one of the first animals to ever live on earth
