On the galápagos islands, the finches that darwin studied tended to have either small beaks or large beaks. the smaller beaks are best at eating soft seeds but are ineffective at cracking large seeds. the larger beaks are best at cracking hard seeds. beaks of intermediate size are inefficient for either seed type. which result of natural selection is at work in this example?
a. stabilizing selectionb. directional selectionc. disruptive selectiond. individual selectione. unnatural selection

The correct answer is option C. "disruptive selection".

Explanation:

Disruptive selection is a type of natural selection at which extreme values for a trait are favored, while intermediate traits are more likely to disappear. In this example the finches tended to have either small beaks or large beaks because small beaks are best at eating soft seeds and large beaks are best at cracking seeds. This is an example of disruptive selection because the two extreme values for the size of beaks are favored.

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.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".