What do both the rho-dependent and rho-independent mechanisms of termination have in common?

During the winter, this species of fox has white fur, but in the summer, it has brown fur. what environmental change may have lead to this fox's fur color? snow cover increase in sun's brightness volcanic eruption global warming

Amale bird-of-paradise uses a dance to attract mates in which it flaps its tail feathers on the ground and jumps around a potential female mate. a different male bird-of-paradise does a similar dance but it jumps around the female in the opposite direction. the female bird is only attracted to one style of dance, in one direction.

Which of these is not a nucleotide base found in dna?