In the past few decades, the way we shop has changed dramatically. We used to buy our goods in traditional shops, on the high street or in department stores. Now, customers are increasingly buying online, where they can order whatever they want directly to their door with the click of a mouse. One in seven sales are now made online and studies suggest that by 2021, global online retail will reach an enormous US$4.8 trillion. Currently, as companies race to improve their internet shopping experience, the trend towards shopping online is predicted to continue.But what is the impact of all this online shopping on the environment? First, researchers estimated that shopping at brick-and-mortar stores for frequently bought items such as toilet paper, shampoo and toothpaste, often results in less greenhouse gas emissions than ordering the products from a company that only sells through the internet. The main reason is because of how people shop online: Many buy items online frequently -- but they only buy a few items per purchase. In addition, frequent online purchases produce more packaging waste, and online items tend to come from different distribution centers. Both factors result in higher greenhouse gas emissions per item. Furthermore, The team modeled their research on the movement of goods from the factory all the way through to the end consumer. They then specifically focused on the part of the retail supply chain called "the last mile" delivery: the distance between a store to a customer, or in the case of online shopping, the distance between the distribution center for the goods to the customer.
Answer the following questions.
1. What are the time signals mentioned in paragraph one?
2. Identify the listing markers in paragraph two. ​