Which set of structures are homologous
a. a butterflys wing and a bats wing
b. a moths eye and a cows eye
c. a beetles leg and a horses leg
d. a whales flipper and a birds wing

My answer is A i hope this really helps u!

Homologous (as I'm sure you know) means  having the same relation, relative position, or structure. Or another way: similar in position, structure, and evolutionary origin but not necessarily in function.

So considering these statements, the most reasonable answer would be D.. They may not have the same function but they're very similar in some ways.

Conclusion

Explanation:

The last step of the scientific method is to form a conclusion. If the data support the hypothesis, then the hypothesis may be the explanation for the phenomena.