Based on the cladogram and the questions provided, here are the answers:
Question 1:
Which characteristic is shared by humans, wallabies, and trout?
Response: notochord
This is the characteristic shared by the three, as both humans (as vertebrates) and wallabies (as mammals) develop from organisms that have a notochord during embryonic development, and trout, being fish, also have a notochord.
Question 2:
Which animals have the closest evolutionary relationship, as shown by the cladogram?
Response: humans and wallabies
Humans and wallabies are both mammals, making them more closely related to each other than to the other animals listed.
Question 3:
A valid conclusion from this cladogram is that
Response: humans and lampreys share a common ancestor.
Cladograms illustrate evolutionary relationships, and if the cladogram depicts humans and lampreys branching from a common ancestor, it supports this conclusion.
If you have further specific details from the cladogram or additional context, let me know for more accurate responses!