Vascular plant is to nonvascular plant as cactus is to

Which plant has a visible leaf modification that will it conserve water in extremely dry environments?

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

In general, characteristics that an organism survive and reproduce become more common over time. what mechanism of evolution causes this?