- Producing thrust causes an animal to move
- A squid produces a stream of water out of its body that causes it to move
- Therefore, a squid produces thrust by pushing water out of its body

- A squid produces thrust by pushing water out of its body
- A rocket engine is used to produce thrust by pushing gases out at a high speed
- Hence, a squid and a rocket engine both produce thrust

- A squid and a rocket engine both produce thrust
- Producing something is a kind of function
- Hence, a squid and a rocket engine both perform the function of producing thrust

- A squid and a rocket engine both perform the function of producing thrust
- If two things perform the same function then those two things are similar
- Therefore, a squid is similar to a rocket engine

Hence, a squid is similar to a rocket engine
Question
A squid is an animal that lives in the ocean. It pumps a stream of water out of its body, causing it to move rapidly. Which of the following mechanical systems moves in a way most similar to the squid?

Context
- Producing thrust causes an animal to move 
- If two things perform the same function then those two things are similar 
- A squid produces a stream of water out of its body that causes it to move 
- A rocket engine is used to produce thrust by pushing gases out at a high speed 
- Producing something is a kind of function