Help please 15 pts!!

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

What are the pros and cons of transect sampling?

Explain how the parts of the peripheral nervous system work with the central nervous system to produce a response to the stimulus