What does the substance of O and H represent?

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

Which would be the most useful source of evidence to support mcneill's contention?

In tomato plants, mendel found that the allele for smooth seeds (s) is dominant, while the allele for wrinkled seeds (s) is recessive. which of these punnett squares shows crosses between two plants heterozygous for smooth seeds? i need this to be answered as soon as ! sry the picture is bad quality