The possible benefits of allied cropping (often referred to as intercropping or agroforestry) in the rainforest would likely include:
- Increased biodiversity - Allied cropping typically encourages a variety of plant species, which can lead to a more diverse ecosystem.
- Maintenance of soil nutrients - Different crops can complement each other in nutrient use, potentially improving soil health and fertility.
The other options, such as "increase use of chemical fertilizers" and "decrease carbon storage," do not generally align with the goals or benefits of allied cropping. "Quick results" is also not specifically a benefit associated with this practice compared to others. Thus, the two correct answers are increased biodiversity and maintenance of soil nutrients.