Arrange the following statements to create the proper order of events in the humoral immune response: 1. the t cell interacts with antigen presented in an mhc-ii molecule. 2. the b cell divides to produce memory b cells and effector b cells. 3. antibodies specific for the antigen are produce in large numbers. 4. the t cell secretes interleukin-2. 5. the b cell presents antigen fragments specific for its surface antibodies using mhc-ii molecules on the cell surface. 1, 3, 2, 5, 4 5, 1, 4, 2, 3 3, 4, 2, 5, 1 4, 2, 5, 1, 3 2, 4, 3, 1, 5

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.

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.