For an xx female to express a recessive sex-linked trait, she must have

The seed coat's most important function is to provide a) a nonstressful environment for the megasporangium. b) the means for dispersal. c) dormancy. d) a nutrient supply for the embryo. e) desiccation resistance.

Radiometric dating is used to tell the absolute age of materials by studying the decay rate of radioactive isotopes. the decay rates of isotopes are constant and are expressed as .

How do living things obtain phosphorus