During dna replication, what two processes must occur before the two strands of a dna molecule can separate?

In fruit flies, gray bodies (g) are dominant over black bodies (g), and brown pigments (n) are dominant over yellow pigments (n). each individual possesses two alleles for each trait. if a fly that is homozygous dominant for both traits is crossed with a fly that is homozygous recessive for both traits, what is the predicted genotype of the offspring.

What were the main components of earth’s earliest atmosphere? oxygen and ammonia hydrogen and helium oxygen and nitrogen hydrogen and nitrogen

With the word calcite wich completes the analogy mineral, erosion, marble, or aragonite