Strands of rna do not contain which of the following bases? a)adenine b)cytosine c)guanine d)thymine

Unlike DNA, RNA doesn't contain Thymine it contains Uracil

Spontaneity tell us the direction of the reaction, but not how fast it goes. gibbs free energy brings together enthalpy, entropy and temperature in one easy formula. g = h - ts. and, finally the sign of delta g is always negative for a spontaneous reaction.