Input: Article: Different fields of science use the term matter in different, and sometimes incompatible, ways. Some of these ways are based on loose historical meanings, from a time when there was no reason to distinguish mass and matter. As such, there is no single universally agreed scientific meaning of the word "matter". Scientifically, the term "mass" is well-defined, but "matter" is not. Sometimes in the field of physics "matter" is simply equated with particles that exhibit rest mass (i.e., that cannot travel at the speed of light), such as quarks and leptons. However, in both physics and chemistry, matter exhibits both wave-like and particle-like properties, the so-called wave–particle duality.

Now answer this question: What word do physicists sometimes consider to be defined as particles exhibiting rest mass?

Output: matter

Input: Article: The city is also in the process of implementing a 5-year and 20 year Bike Action Plan with a goal of attaining 14 to 35% bicycle transportation mode share by 2030 through the installation of enhanced bicycle infrastructure throughout the city. Other environmentally focused initiatives include curbside recycling, curbside composting bins (in addition to trash, yard-waste, and recycle bins), farmers' markets, community gardens, garden-share, an urban forest initiative, a hazardous materials home-collection service, green business certification, and a municipal bus system which is currently being revamped to integrate with the soon-to-open Expo Line.

Now answer this question: What type of business certification do they plan on expanding?

Output: green

Input: Article: In the first centuries AD, political and administrative subdivisions began to emerge in Estonia. Two larger subdivisions appeared: the province (Estonian: kihelkond) and the land (Estonian: maakond). Several elderships or villages made up a province. Nearly all provinces had at least one fortress. The king or other highest administrative official elder directed the defense of the local area. By the thirteenth century Estonia consisted of the following provinces: Revala, Harjumaa, Saaremaa, Hiiumaa, Läänemaa, Alempois, Sakala, Ugandi, Jogentagana, Soopoolitse, Vaiga, Mõhu, Nurmekund, Järvamaa and Virumaa.

Now answer this question: When did political subgroups begin to appear in Estonia?

Output:
first centuries AD