Auxin, The substance responsible for cell elongation is auxin. This phytohormone is formed in cells at the tip of the shoot and is then passed from cell to cell.
DNA replication begins when something called Helicase (an enzyme) unwinds the helix structure of the DNA. It does this so that Primase can then come along and set down an RNA primer.
A cladogram is an image or a diagram that shows us an evolutionary relationship between different organisms. Up at the top we find the different organisms and their names. Along the side is where we find their characteristics. Anything that is past each characteristic will have that characteristic as you move up the cladogram. This diagram also shows which organisms are most closely related to one another.
Please see the image for an example. In this example we can see that the Koalas evolved after the trout.
I hope this helps, Regards.