The sun spectrum contains spectral lines from natural iron and calcium as well as natural magnesium of the choices below which could be the surface temperature of the sun

a- multicellular

b-eukaryotic

c-no cell wall

d-heterotrophic

e-autotrophic

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.