Article: A group is called finite if it has a finite number of elements. The number of elements is called the order of the group. An important class is the symmetric groups SN, the groups of permutations of N letters. For example, the symmetric group on 3 letters S3 is the group consisting of all possible orderings of the three letters ABC, i.e. contains the elements ABC, ACB, ..., up to CBA, in total 6 (or 3 factorial) elements. This class is fundamental insofar as any finite group can be expressed as a subgroup of a symmetric group SN for a suitable integer N (Cayley's theorem). Parallel to the group of symmetries of the square above, S3 can also be interpreted as the group of symmetries of an equilateral triangle.

Question: What can be described as the group of symmetries of an equilateral triangle?
Ans: S3

Article: The net quality of a ground reflection depends on the topography of the surface. When the irregularities of the surface are much smaller than the wavelength, we are in the regime of specular reflection, and the receiver sees both the real antenna and an image of the antenna under the ground due to reflection. But if the ground has irregularities not small compared to the wavelength, reflections will not be coherent but shifted by random phases. With shorter wavelengths (higher frequencies), this is generally the case.

Question: What frequencies is associated with shorter wavelengths?
Ans: higher frequencies

Article: Physiologically, the function of the brain is to exert centralized control over the other organs of the body. The brain acts on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones. This centralized control allows rapid and coordinated responses to changes in the environment. Some basic types of responsiveness such as reflexes can be mediated by the spinal cord or peripheral ganglia, but sophisticated purposeful control of behavior based on complex sensory input requires the information integrating capabilities of a centralized brain.

Question: Reflexes only require one of what two structures in a body?
Ans: spinal cord or peripheral ganglia

Article: As reflected in the 2010 United States Census, Alaska has a total of 355 incorporated cities and census-designated places (CDPs). The tally of cities includes four unified municipalities, essentially the equivalent of a consolidated citycounty. The majority of these communities are located in the rural expanse of Alaska known as "The Bush" and are unconnected to the contiguous North American road network. The table at the bottom of this section lists the 100 largest cities and census-designated places in Alaska, in population order.

Question: Are the majority of CDPs connected or disconnected from the North American road network?
Ans:
unconnected