Interested in the proportion of nucleotides in the DNA of skin cells from a During their work to establish the structure of DNA, Watson and Crick were
particular organism. They considered the results from three different samples
done in the same laboratory, as shown in the table below.
Percentage of each nucleotide
Sample 1 Sample 2 Sample 3
Nucleotides in DNA
А
29
31
29
T
31
30
30
19
с
21
20
G
19
21
20
Why did Watson and Crick consider results from three samples?

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population.b) the separated population is small, and genetic drift occurs.c) the isolated population is exposed to different selection pressures than the ancestral population.d) different mutations begin to distinguish the gene pools of the separated populations.e) gene flow between the two populations is extensive.