For each situation, indicate the type of speciation described.

hundreds of years ago true fruit flies in the america west coast only laid eggs on native hawthorns (a native apple tree), but today one group of true fruit flies lay eggs on hawthorns, and one group lay eggs on imported apples.

[ choose ] sympatric speciation allopatric speciation
continents drift apart and separate previously connected lineages.

[ choose ] sympatric speciation allopatric speciation
different environments on two sides of a barrier cause populations to diverge.

[ choose ] sympatric speciation allopatric speciation
there are nine species of cichlid fish living in lake bermin (an isolated crater lake in cameroon). genetic data show that they are each others closest relatives, implying that they speciated there. the lake is only 0.6 km2 in surface area and 14.5 m deep, with no river feeders into or out of the lake.

[ choose ] sympatric speciation allopatric speciation
a mountain range separates formerly connected populations of rabbits.

the cell theory states that all living things including animals, as well as plants, are made of cells.

answer; i believe the correct answer is (a)0

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.