If organisms a, b, and c belong to the same class but to different orders and if organisms d, e, and f belong to the same order but to different families, which of the following pairs of organisms would be
expected to show the greatest degree of structural homology?

a. a and b
b. a and c
c. b and d
d. c and f
e. d and f

The correct answer is e. D and F

Explanation:

Organisms can be classified into seven major levels that are kingdom, phylum, class, order, family, genus, and family. The highest level of classification is the kingdom and the lowest level of classification is the species.

When we move from the higher level of organization i.e., from kingdom to the lower level of classification i.e., towards species then the similarities between the organisms increase and the number of organisms decrease and vice versa happens when we move from species to kingdom.

So, the class is a higher level of classification and order is at lower level than class, therefore, organisms in order will have the greatest degree of structural homology. Therefore the right answer is e. D and F.