What is the key organism that ensures the
nitrogen cycle can run properly?

Which best describes a rhinovirus? o a. a virus that causes a common cold o b. a protective shell around a virus o c. a tube the comes off a virus o d. a piece of dna transferred by a virus

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 diagram below, the northern hemisphere would be in what season at position a a. fall b. winter c. summer d. spring