Grasslands and the tundra are both home to large herds of grazing animals. what makes caribou different from the herbivores of warmer climates?

a. caribou are migratory and only spend summers in the tundra.

b. caribou have adapted to the lack of vegetation by eating animals as well.

c. caribou have a thicker coat of fur and wider hooves.

d. caribou have larger ears to allow excess heat to escape.

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.