Please choose the correct ending to complete the given sentence: Education and Communications: [header] How to study the chemical reactions of ammonia [title] Research the use of ammonia in farming. [step] Nitrogen is essential to the growth of plants. You can mix ammonia in the soil to be metabolized by bacteria present in the soil.

Ending1: For ammonia, you usually dilute it with water if it is very acidic. Ammonia traps nitrogen in geodes which can degrade the soil's nitrogen into sludge (rise scum). Ending2: The following plants are popular sources of ammonia : [substeps] Zinnias. Zinnias are often used for medicinal purposes. Ending3: The resulting compounds are nitrite (no) and nitrate (no). These compounds can be readily used by the plants for growth. Ending4: Alternatively, bde is useful in the production of nitrogen, in the ph of the soil. [substeps] Nitrogen and nitrogen are not distinct sources of nitrogen, and therefore plants without ammonia can.

Answer format: ending1/ending2/ending3/ending4