Invertebrates with spine skin are echinodemata which would include animals like

Aresearcher has developed two stains for use with seed plants. one stains sporophyte tissue blue; the other stains gametophyte tissue red. if the researcher exposes pollen grains to both stains, and then rinses away the excess stain, what should occur? a) the pollen grains will be pure red. b) the pollen grains will be pure blue. c) the pollen grains will have red interiors and blue exteriors. d) the pollen grains will have blue interiors and red exteriors.

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

What is the difference between an igneous, sedimentary and metamorphic rock