List and explain the 6 conditions Darwin says influence natural selection leading to evolutions of a species?

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 element forms the basis of all organic organisms a carbon b oxygen c hydrogen d nitrogen

Based on the topographic map of mt. st. helens, what is the contour interval of the volcano about height is 2,950 m?