What are valence electrons? why are valence electrons important?

Compare and contrast the relative importance of the sporophyte vs gametophyte generation between nonvascular plants (bryophytes), seedless vascular plants and seed plants, and explain the ecological significance of a larger sporophyte generation

Which organisms have pharyngeal arches that develop from all three germ layers and go through the same development stages as embryos? 1.bird 2.ladybug 3.starfish 4.snake

Land conservation is a worldwide priority. there are several methods to prevent the loss of land due to a variety of reasons. which method is not a way to conserve land? a) sea walls b) rainwater harvesting c) limits on clear cuts of forests d) cut and burn methods of clearing land