Question

below is a table showing the pairwise distance between the ribosomal dna 18s nucleotide sequence in several lymnaeid and proximal lymnaeid species. the species have been given identification numbers for easy usage.

species	1	2	3	4	5	6	7	8	9	10	11	12	13
2	2
3	6	6
4	15	15	15
5	13	12	15	4
6	14	14	16	9	7
7	13	15	15	15	15	11
8	17	19	19	16	16	13	5
9	14	16	16	16	16	11	4	5
10	11	12	12	12	12	13	8	10	8
11	17	19	13	13	13	10	11	11	11	8
12	58	60	58	52	54	51	56	55	57	54	52
13	58	58	57	52	54	50	55	54	56	53	53	25

which of the conclusions below is best supported by the information in the table?

a species 9 and species 7 are more closely related than species 3 and species 2.
b species 10 and species 6 are less closely related than species 5 species 3.
c species 10 and species 7 are more closely related than species 3 and species 2.
d species 8 and species 5 are less closely related than species 13 species 3.

Explanation:

To determine the correct conclusion, we analyze the pairwise distances (smaller distance means closer relatedness):

• Option A: Distance between species 9 and 7 is 4; distance between species 3 and 2 is 6. Since \(4 < 6\), species 9 and 7 are more closely related. This is correct.
• Option B: Distance between species 10 and 6 is 13; distance between species 5 and 3 is 15. Since \(13 < 15\), species 10 and 6 are more closely related (contradicts "less closely related").
• Option C: Distance between species 10 and 7 is 8; distance between species 3 and 2 is 6. Since \(8 > 6\), species 10 and 7 are less closely related (contradicts "more closely related").
• Option D: Distance between species 8 and 5 is 16; distance between species 13 and 3 is 57. Since \(16 < 57\), species 8 and 5 are more closely related (contradicts "less closely related").

Answer:

A. Species 9 and species 7 are more closely related than species 3 and species 2.