- Eating something has a negative impact on that something
- Animals eat cacti
- Hence, animals have a negative impact on cacti

- Animals have a negative impact on cacti
- If something has a negative impact on an organism then that organism must protect itself from that something
- Hence, a cactus must protect itself from animals

- A spine is a part of a cactus that is hard and located on the outside of the cactus
- Something hard / something strong can be used for protection
- So, a spine is a part of a cactus used for protection

- A cactus must protect itself from animals
- A spine is a part of a cactus used for protection
- So, a cactus spine is a part of a cactus for protecting the cactus from animals

- A cactus spine is a part of a cactus for protecting the cactus from animals
- Protecting a living thing has a positive impact on that living thing 's survival
- Therefore, a cactus spine has a positive impact on a cactus's survival by protecting the cactus from animals

Therefore, a cactus spine has a positive impact on a cactus's survival by protecting the cactus from animals
Question: How do the spines of a cactus help it survive?
Context: - Eating something has a negative impact on that something 
- A spine is a part of a cactus that is hard and located on the outside of the cactus 
- Animals eat cacti 
- Something hard / something strong can be used for protection 
- If something has a negative impact on an organism then that organism must protect itself from that something 
- Protecting a living thing has a positive impact on that living thing 's survival