Why do we see different phases of the moon ? need immmediatley !

According to the federal regulations, which of the following studies meets the definition of research with human subjects? a study of twenty 4th grade classrooms in which researchers ask the schools to systematically vary the time of day reading is taught, and collect weekly assessments of reading comprehension for each child over a three-month period.the collection of data, by a playground designer hired by the superintendent of schools, about the physical dimensions of school playgrounds, presence of fencing, and the kinds of equipment currently provided.a feasibility study for implementing a year-round school program, focusing on economic issues such a facilities utilization and transportation costs.an analysis of aggregate data comparing statewide high school graduation rates provided by the state department of public instruction, using county tax information.

This description of the "firm league of friendship" of states is a quotation from the

Sandra lives in the heart of a large city. lately, there have been robberies on several of the streets near where sandra lives but none on her street. sandra and her neighbors believe that they have not seen any crime on their street because they know each other, notice when strangers or strange cars are in the neighborhood, and have a mix of old retired couples and young families who use the neighborhood at different times of the day. jane jacobs would see this as an example of: