You may talk about this picture:
A: it is an
ionic bond (which is a strong interaction, between two close atoms which has a large difference in their charges, like azote and oxygen)
B: is a
hydrogen bond (between O in a side and H in the other side)
C: it could be a
Van der Waals bond (small interaction between Carbon and hydrogen from different sides (London interaction))
D:
Hydrogen bond (between the Oxygen and hydrogen from different sides)
E: it's an
ionic bond
The nitrogenous bases in DNA are adenine, guanine, thymine, and cytosine.
The nitrogenous bases in RNA are adenine, guanine, uracil, and cytosine.
So the base in RNA that is different than in DNA is uracil.
Hope this helps.
B.) crystallization. Igneous rocks turn into sediments through the process of crystallization.