Suppose a similar experiment was set up to measure changes in air composition immediately before and two days after twenty potted plants were placed in a clear, sealed aquarium near a window. Percentages of Chemicals in Air O2 CO2 Before 20.94% 0.03% After ? ? How would the second row of values in the plant experiment most likely compare to the second row of values in the original experiment? Oxygen levels would be higher, but carbon dioxide levels would be lower. Carbon dioxide levels would be higher, but oxygen levels would be lower. Oxygen levels would be higher, but carbon dioxide levels would be the same. Carbon dioxide levels would be higher, but oxygen levels would be the same. Mark this and return Save and Exit Next

A

Explanation:

Oxygen levels would be higher, but carbon dioxide levels would be lower.

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.

a = executive branch; b = judicial branch