Evolution is affected by the random movement of alleles from one population
to another. This is known as gene flow. Which of the following examples does
NOT represent gene flow?

well, i believe that the answer is 2. : 3

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.

answer: dna

because all cells have genes