1. applied research
2. basic research
3. control
4. dependent variable
5. empirical evidence
6. hypothesis
7. independent variable
need definitions

Applied Research: It is a research conducted to find solutions for specific problems in a particular field of studies. Example, health effects on food that are genetically modified.

Basic research: It is basic research on any field to have a clear understanding of something from the existing knowledge. Example, the study on evolution of the living organisms.

Control:  To increase the reliability of the result the scientific experiments decrease the number of variables (depending factors) in the experiment.

Dependent variable: This is a variable that determines the outcome of the result of an experiment depending on the independent variables. For example,  stress influence the heart rate. Heart rate is a dependent variable.

Empirical evidence: It is the collection of scientific facts directly or indirectly. These facts support the scientific nature of the research. For example,  measuring temperature, water freezing at a particular temperature and pressure.

Hypothesis: It is an explanation or assumption of a phenomenon based on limited empirical evidence. This is the first step of the research.

Independent variable: This is a variable that the experimenter has control to change. For example, stress influence the heart rate. Stress is an independent variable.

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.

a 2,000 calorie based diet.