The text defines psychology as the scientific investigation of behaviour and:Question 2Answera.culture.b.observation.c.consciousness.d.mental processes.

Break Down the Problem

1. Identify the key term in the definition of psychology.
2. Determine the correct option that completes the definition accurately.

Relevant Concepts

• Psychology is defined as the study of behavior as well as underlying factors.
• The options provided can be analyzed in terms of their relevance to psychology.

Analysis and Detail

1. Option A: Culture - While culture influences behavior, it does not specifically match the fundamental aspects of psychology's definition.
2. Option B: Observation - Observation is a method used in psychology but does not complete the definition.
3. Option C: Consciousness - Consciousness is an area of study within psychology but is not comprehensive.
4. Option D: Mental Processes - This encompasses cognitive functions such as thinking, memory, and decision-making, making it a suitable match.

Verify and Summarize

Upon analyzing each option with respect to the academic definition of psychology, "mental processes" appears to be the most fitting completion of the definition provided.

Final Answer

d. mental processes.