01.04.14
Selena made a chart to group adaptations in birds based
on their main functions.
Which functions should Selena use as headings to
complete the chart?
Adaptations in Birds
contour feathers
nearly hollow bones
strong chest muscles
crop
gizzard
strong beak
O X: Flight
Y Feeding and Digestion
OX: Maintaining Body Temperature
Y: Circulating Oxygen
OX: Flight
Y: Circulating Oxygen
X: Maintaining Body Temperature
Y: Feeding and Digestion
Save and Exit

the median of the data is 4.5.

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.

layer 3 is younger than layer 6.