If intelligent extraterrestrials visited Earth 475 million years ago,and then again 300 million years ago (at the close of the Carboniferous period),what trends would they have noticed in Earth's terrestrial vegetation over this period?
1)a trend from dominant gametophytes to dominant sporophytes
2)a trend from no true leaves to microphylls to megaphylls
3)a trend from plants that grow just above the soil surface to "overtopping" plants
4)a trend toward increased lignification of conducting systems

Question

Quizplus · Accepted Answer

The trends in terrestrial vegetation over this period include a shift from dominant gametophytes to dominant sporophytes, the evolution of plants from having no true leaves to developing microphylls and then megaphylls, a transition from plants that grow just above the soil surface to plants capable of "overtopping" (growing taller than their neighbors), and an increase in the lignification of conducting systems to support taller growth and efficient nutrient transport.

If Intelligent Extraterrestrials Visited Earth 475 Million Years Ago,and Then