Which of the following best describes how comparative anatomy can be used to determine the evolutionary relationship between two organisms?
Answer

Comparing the physical traits of two organisms makes it possible to determine how long ago they shared a common ancestor.

Organisms that have a great deal of physical similarity are more likely to share a common ancestor than two organisms with few physical traits in common.

Studying the physical differences between two organisms will show which organism evolved from the other.

Two species that have few physical traits in common

Question

Which of the following best describes how comparative anatomy can be used to determine the evolutionary relationship between two organisms?
Answer
		
Comparing the physical traits of two organisms makes it possible to determine how long ago they shared a common ancestor.
		
Organisms that have a great deal of physical similarity are more likely to share a common ancestor than two organisms with few physical traits in common.
		
Studying the physical differences between two organisms will show which organism evolved from the other.
		
Two species that have few physical traits in common

anonymous · Answer

the rest of four is; ....do not share a common ancestor and most likely evolved from different species.

anonymous · Answer

This one I'm not completely sure, but I will just give it a try
comparative anatomy mostly deals with physical structure, homologus, analogous etc
so I will take out the options about traits 
This is also used to determine the common ancestor but not who evolve from who 
I'm going with option #2, correct me if I am wrong

anonymous · Answer

and btw, that is homologous structure
have same physical similarity but not the structure 
so most likely they come from the common ancestor but have a different use of that structure