What is free nitrogen? Nitrogen gas is called "free" nitrogen, meaning it is not combined with other kinds of atoms. Most organisms can use nitrogen only once it has been "fixed," or combined with other elements to form nitrogen-containing compounds.

Question#29: why does the tropical ocean have a greater temperature range than the temperate ocean?

Which of the following types of stars is most likely to end up as a supernova? in graph a, the curve peaks at 800 nm, in the red section of the visible light spectrum. in graph b, the curve peaks at 550 nm, in the green section of the visible light spectrum. in graph c, the curve peaks at 450 nm, in the blue section of the visible light spectrum. in graph d, the curve peaks at 300 nm, in the violet section of the visible light spectrum. a b c d

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic