This feature allows you to mark a selection in query 
designer as constant, navigation and filtering has no 
effect on this during runtime.

The master data is loaded first. Because , it determines how transactions happens and which way it is to be happened. The master data is building block, upon which we maintain the record of the transactions as they takes place.

Hi I believe that this question came up in relation to 
Generic Extractors (Which can be created on 
Table/View,Function Module and Infoset query). View is a 
combination of two or more tables with keys being commmon 
among these tables and doesn't hold phisical data. Function 
module is a modularization technique where in you pick data 
from different tables checking the data in these tables 
against certain conditions.

Added to the above answer, Function Module can even access 
the Pool tables, whereas View can not.

Standard DSO can have one user and one operation at a time. 
Write optimized DSO is used to get unique records

It is a cell specific definition.(intersection of two 
structures one char structure and one key firgure structure)

Fit gap means, before implementing the SAP all the business data is in the form of documents, we cannot keep this data as is in the SAP. There should be a gap. So by filling this gap, we make configuration with the help of these documents. This is called as fit gap analysis.

Data Target refers to an object where there is a physical 
storage of data. Info-provider refers  to a logical object 
where there is no physical storage of data.

Infoproviders are objects for which you can create and execute queries in SAP BI.

These includes objects that physically store data – the data targets, such as Infocube, DSO, characteristics Infoobjects. They also include objects that do not store physical data, such as Infosets, Virtual Infoproviders and Multiproviders.

Infoproviders is a generic term used to describe any objects or views relevant to reporting.

Data Targets become InfoProviders if they are used for BEx Reporting.