Context: Animals are also involved in the distribution of seeds. Fruit, which is formed by the enlargement of flower parts, is frequently a seed-dispersal tool that attracts animals to eat or otherwise disturb it, incidentally scattering the seeds it contains (see frugivory). Although many such mutualistic relationships remain too fragile to survive competition and to spread widely, flowering proved to be an unusually effective means of reproduction, spreading (whatever its origin) to become the dominant form of land plant life.

Question: What are animals also a part of?
Answer: distribution of seeds

Question: What did the enlargement of flower parts evolve to form?
Answer: Fruit

Question: What does a plant get out of forming fruit?
Answer: seed-dispersal

Question: What are many mutualistic relationships, thus failing to survive competition? 
Answer: fragile

Question: What turned out to be unusually effective for plants to reproduce?
Answer: flowering

Question: What did competition prove to be effective at doing?
Answer: Unanswerable

Question: What did mutualistic relationships spread to eventually become?
Answer: Unanswerable

Question: How does a plant benefit from competition?
Answer: Unanswerable

Question: What reproductive method spread widely but made plants fragile?
Answer: Unanswerable

Question: What did accidentally scattering seeds help flower parts evolve to form?
Answer: Unanswerable