Answer:
1.Concepts and constructs are the stuff of theory; they are abstractions that are used to explain relations and general patterns of behavior. Variables are concepts that have operational measures. Variables are the properties of the object being studied; they are symbols that take on at least two numerical values.
2.Theories are supported by evidence from many different sources, and may contain one or several laws. A common misconception is that scientific theories are rudimentary ideas that will eventually graduate into scientific laws when enough data and evidence have been accumulated.
3.Systematic literature review can be divided into two categories: meta-analysis and meta-synthesis. ... Integrative literature review reviews, critiques, and synthesizes secondary data about research topic in an integrated way such that new frameworks and perspectives on the topic are generated.
4.The gap, also considered the missing piece or pieces in the research literature, is the area that has not yet been explored or is under-explored. This could be a population or sample (size, type, location, etc.), research method, data collection and/or analysis, or other research variables or conditions.
