1. Platypus, Brown Bear, Lion, and House Cat.
2. Brown Bear.
3. House Cat.
In this graph you are basically going down the line (or up towards the house cat) looking at the qualities each animal has. So whatever is on the bottom (hair and mammary glands) all animals above it has it. If the quality passes the animal, the animal doesn’t have that quality.
Hopefully this explanation is clearer with the answers.