Scientists divide earth into three main layers: the core, the mantle, and the crust. how are these three layers identified?

by their chemical composition

by their structural features

by their plate tectonics

by their physical properties

Plants are used for so many things. in your house alone, you can probably look around you and see where plants have been used. for this project, you will identify various uses of plants in your home. directions make a list of objects, products, and any other items around your house where plants were involved in the production of the item. you should have a list of at least twenty items. then respond to the following questions: note: your list of objects and the answers following should be at least 200 words in length. what if plants no longer existed on earth? how would your life be different?

Ablastocyst is a group of cells that forms after a human egg is fertilized. the blastocyst consists of two types of cells. some of these cells will become the placenta. what do the other cells develop into?

Apopulation of black bears depends on salmon from a stream for food. if a drought causes the stream to run dry one year, how will this likely impact the black bear population?