Select the correct answer.
Which statement forms part of cell theory?
O A. Cell organelles are capable of reproducing themselves.
OB. Cells differ in shape, but they have identical components.
C. All cells begin life as prokaryotic cells.
OD. All living things are made up of cells.

well the answer is 2!

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.