- A structure is a kind of feature
- A part of a living thing is a natural structure
- Hence, a part of something is a feature of something

- A part of something is a feature of something
- Roots are a part of a plant
- Therefore, roots are a feature of plants

- Grass is a kind of green plant
- A tree is a kind of plant
- Hence, a tree and grass are both kinds of plants

- Roots are a feature of plants
- A tree and grass are both kinds of plants
- Therefore, roots are a feature of both trees and grass

- Roots are a feature of both trees and grass
- If two things have the same features then those two things are alike
- Therefore, a tree and grass are alike because they both have roots

So, a tree and grass are alike because they both have roots
[Question]How are a tree and grass alike?
[Context]- A structure is a kind of feature 
- Grass is a kind of green plant 
- A tree is a kind of plant 
- Roots are a part of a plant 
- A part of a living thing is a natural structure 
- If two things have the same features then those two things are alike