Just months after cargo volumes plunged amid the COVID-19 pandemic, the nation’s ports are staging a comeback as falling product inventory levels at warehouses, stores and medical facilities are being quickly replenished. Simultaneously, the economy shows signs of recovery, and the holiday shopping season is set to begin. The nation’s busiest port, the Port of Los Angeles, set a record in September, processing 13.3% more 20-foot-equivalent units, totaling 883,625 containers compared with 779,902 last year. Officials said imports were key to the recovery as the economies of China and other Asian nations recover from the coronavirus.