Answer:
internal validity
Explanation:
The internal validity measures the degree to which the research is correct. This is done by determining the number of confounding variable.
A confounding variable is the variable that influences both the independent and dependent variable. Only the independent variable should influence the dependent variable.
When the confounding variables found in the research is low the internal validity of the research increases and if the confounding variables found in the research is high the internal validity of the research decreases.
Here, Professor X is worried that a confounding variable is influencing his dependent variable so he is concerned about the internal validity of his experiment.
Answer:
- Chemical factors;
The chemical factors like the salinity and the composition are very important for the formation of the soil, as well as for determining the type of soil.
- Physical factors;
The most important of the physical factors are the erosion and deposition. While the erosion removes layers of soil from a certain places, the deposition brings that material on another place and makes layers which set of a new start for soil formation on another place.
- Climatic factors;
The climate is extremely important because it sets the basic for the soil formation. Different types of climate result in different types of soil, and the fact that the climate is the factor that enables certain plants to grow in certain conditions, makes it possible for the soil to become richer or poorer depending on the biomass available.
Explanation:
Research
Studying fossil
Interview
Analysis
