What are some ideas of human pedigrees? for example mendels principles of genetics.

In addition to seeds, which of the following characteristics are unique to the seed-producing plants? a) sporopollenin b) lignin present in cell walls c) pollen d) use of air currents as a dispersal agent e) megaphylls

How can scientists test their ideas about the origin of the universe if they can't physically interact with or study?

Which layer will become saturated first when rain falls?