Read the following article and answer the question. Article: Imagine life without the Internet -- not being able to chat with your friends or look up information for your homework or research project. That is the reality for nearly two-thirds of our world's population, either because they cannot afford WiFi access or are located in remote, inaccessible areas. Now Google has decided to do something about that. Google's Project Loon will attempt to send balloons high up into our earth's atmosphere in 2015. Each balloon will be equipped with a mini computer and a WiFi radio that will send Internet signals over the places it is floating over. The network equipment on Google balloons will communicate with a special antenna attached to each user's home. These antennae are in turn connected to a local Internet Service Provider. Each balloon will also communicate with each other to hand over signals as one floats out of an area, and another floats in. The balloons are 15 meters wide and made of a material that is three times thicker than the plastic bag at the supermarket. This helps them defend themselves against cold temperatures and changing air pressure. Google balloons will circle the earth at a height of 20 kilometers-- in a layer of our atmosphere known as the stratosphere . This is higher than the altitude at which planes fly. Once the balloons reach the desired altitude after being released from the earth, they will ride on air currents. What keeps these balloons from flying away? They will be controlled by people at the Project Loon command center. A pump operating on solar power will fill the balloon with gas to raise it or let gas out to lower it, based on instructions. This allows the balloon to float on different air currents which are moving either clockwise or anti-clockwise. There is no doubt that this technology can bring education to many children, weather information to farmers, and communication to natural disaster areas. However, one big question remains -- will some countries be comfortable with balloons above their heads? There could be concerns... Question: According to the text, Google balloons_. Answer:
will be placed in the stratosphere