。
The price of rice dropped.
Literal
Rice's price [subject-が] dropped.
下がった is the plain past of 下がる ('to drop, fall'). A minimal factual statement: subject + past verb. The simple past frames the drop as a discrete completed event, in contrast with the ~ている form (e.g., 下がっている 'is dropping'), which would frame it as an ongoing process. Choosing tense changes the whole rhetorical posture.