Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

Modeled after US hot website.com, group buying websites are now popular in China. These websites use the power of group buying to get competitive discounts for a daily deal on some best stuff to do, see, eat and buy in the cities across China. Discounts are available within just one click. Zhao lei, a software engineer in Beijing, loves the one-hour lunch break at noon,as it is the best time for him to check "today's special" at his favorite group buying websites . Sometimes he searches for great deals at directory sites devoted to the new shopping space. Zhao spends around 800 yuan($117.65) on group buying every month, mostly to buy food coupons for eating at some nice restaurants and occasionally to find something fun to do. " I love group buying. In addition to the competitive discounts it offers, it helps me get something fun, exciting and new, and such surprises give me a reason to try something new," he said. When he finds a really good bargain, he will send the link to friends or colleagues through MSN,QQ, or e-mail, or share the information at some social networking websites. In doing so, he often gets a certain cut off the price. At some sites, buyers are invited to leave notes about what they want to buy and the website will consider it if similar applications reach a certain number. That is how Zuo got her digital camera after waiting for two months. "It is cool. I want to buy a new digitgal camera for my trip to Switzerland this winter, but I never expected such cheap prices!" Zuo said.
What is the passage mainly about?

Temperature is a measure of how fast the atoms in a material are vibrating. High temperature particles vibrate faster than low temperature particles. Rapidly vibrating atoms smash together, which generates heat. As a material cools down, the atoms vibrate more slowly and collide less frequently. As a result, they emit less heat. What is the difference between heat and temperature? Temperature measures how fast a materials atoms are vibrating. Heat measures the materials total energy. Heat energy is transferred between physical entities. Heat is taken in or released when an object changes state, or changes from a gas to a liquid, or a liquid to a solid. This heat is called latent heat. When a substance changes state, latent heat is released or absorbed. A substance that is changing its state of matter does not change temperature. All of the energy that is released or absorbed goes toward changing the materials state. For example, imagine a pot of boiling water on a stove burner: that water is at 100o C (212o F). If you increase the temperature of the burner, more heat enters the water. The water remains at its boiling temperature, but the additional energy goes into changing the water from liquid to gas. With more heat the water evaporates more rapidly. When water changes from a liquid to a gas it takes in heat. Since evaporation takes in heat, this is called evaporative cooling. Evaporative cooling is an inexpensive way to cool homes in hot, dry areas. Substances also differ in their specific heat, the amount of energy needed to raise the temperature of one gram of the material by 1.0o C (1.8o F). Water has a very high specific heat, which means it takes a lot of energy to change the temperature of water. Lets compare a puddle and asphalt, for example. If you are walking barefoot on a sunny day, which would you rather walk across, the shallow puddle or an asphalt parking lot? Because of its high specific heat, the water stays cooler than the asphalt, even though it receives the same amount of solar radiation.
the amount of energy needed to raise the temperature of one gram of material by 1.0oc.

Between 1992 and 1994, Porsche Motorsports Research and Development built and provided a full "Race" version (stripped out 968 Turbo S) for Porsches customer race teams. The 968 Turbo RS was available in two variations; a version using the K27 turbocharger from the Turbo S, which was built to the German ADAC GT specification (ballast added to bring the car up to the 1,350 kg minimum weight limit), and an international spec version which used a KKK L41 turbocharger producing and was reduced to 1,212 kg in weight. Only 4 were ever produced ; 1 Guards Red (WPOZZZ96ZNS820065), 1 Speed Yellow (WPOZZZ96ZPS896061), 1 Black (WPOZZZ96ZPS896062) and 1 White (WPOZZZ96ZPS896063). These are the rarest 968s ever produced.

Which variation of the 968 Turbo RS weighed less?