Final answer:
The revised sentence using imagery to create a bleak mood is, 'I saw so many grave markers by the side of the trail-crudely lettered, sun-bleached, wind-scoured.' This version emphasizes the desolation and hardship of the trail.
Step-by-step explanation:
To revise sentence 9 using imagery to create a bleak mood, the best option is: I saw so many grave markers by the side of the trail-crudely lettered, sun-bleached, wind-scoured. This revision paints a vivid picture of the desolate and sorrowful environment that pioneers faced on the Oregon Trail. It uses specific and concrete details to portray the hardships and the harsh reality of death that was an ever-present danger along the journey.