They have developed a complex structure of classes, incomes and property holdings. (blog.politics.ox.ac.uk)
Scientists Reveal First Structure of a Class of Proteins that Sniff Out Signals Guiding Blood Cell Movement (scripps.edu)
Careful structuring of classes allows for every child to be known and loved, while providing a broad range of learning opportunities in academics, visual and performing arts, athletics, service, and leadership. (chicagoparent.com)