Help my biology project is due today

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

In the ocean why are the greatest amount of primary producers found in the epipelagic zone and how does that affect biodiversity

Describe your dna model. which part do the straws represent? the pushpins? the paper clips and the black dots you made with the marker?