In order for meiosis to create four, genetically different gametes, dna replication must occur. which of these best describes when dna replication would occur during meiosis?
a) prior to meiosis i
b) prior to meiosis ii
c) prophase i in meiosis i
d) prior to meiosis i and meiosis ii

substitution is the answer in this case

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.