A class of AP Environmental Science students wanted to recreate a small model of an ecosystem similar to that on Island C to aid in their study of the interactions between plants, worms, and snails. The students were exploring how earthworms act as an important species in the cycling of nutrients. The students built three different terrariums like the one shown below and altered the
number of earthworms in each terrarium in the following manner
• Terrarium I had zero earthworms added
Terrarium 2 had five earthworms added
• Terrarium 3 had ten earthworms added
One snail was added to each terrarium, and each system contained the same number of grass seedlings, the same type of loam soil, and the same amount of water. After three weeks, the students
measured the amount of ammonia in the soil