Explain the change of color that often occurs in leaves in the autumn in simple terms.

Check all that apply diatoms are marine algae that have a shell made of silica, what are some of the uses of the silica shell after the diatoms die? 1.the shells make up the diatomaceous earth used in filters 2.it can be used as an ingredient in abrasives 3.they are used in food products 4.the shells can be used in some insulating materials

Which identifies the main purpose of biological taxonomy?

What was the land like over 500 million years ago? what was under the sea?