Holism and reductionism - Levels of explanation

Question 1

What are levels of explanation?

Answer 1

Explanations vary from those that are lower level focusing on basic components/units. (Reductionist)
To
Those at a higher holistic multivariable level

Question 2

What can lead to a high level of explanation

Answer 2

Combining different approaches to explain a behaviour.

Social psychology
Cognitive psychology
Behaviourism
Biological psychology