What condition absolutely must be present in a population before evolution can act upon it ?

Explain how the number of similarities between the embryos from early stage to late stage is used as evidence of a common ancestry

How does human environment effect the biosphere

Which of these is an example of land degradation? a. containers designed to store pollutants leak. b. fertilizers provide too many nutrients to crops. c. garbage is buried so the land can be reclaimed later. d. a drought kills all the plants in an area, leaving bare land