How many different unrooted tree arrangements are possible for a phylogenetic tree relating five species?
A) 5
B) 15
C) 25
D) 105

Question

Quizplus · Accepted Answer

The number of different unrooted tree arrangements for five species can be calculated using the formula (2n-5)!!, where "n" is the number of species. 
Therefore, for five species, the number of unrooted tree arrangements is (2x5-5)!! = 15. 
Thus, the correct answer is option B, with 15 possible unrooted tree arrangements.

How Many Different Unrooted Tree Arrangements Are Possible for a Phylogenetic