________ the study of differences and similarities in behaviour among men and also between man and animal.

Sure, let's break down the question step by step to find the appropriate word to fill in the blank.

1. Identify the context: The sentence is describing a field of study that compares behaviors among humans and between humans and animals.

2. Key terms:

   • Differences and similarities in behavior
   • Among men (humans)
   • Between man (humans) and animal

3. Relevant fields of study:

   • Comparative Psychology: This is the branch of psychology that studies the similarities and differences in behavior across species, including humans and animals.
   • Ethology: This is the scientific study of animal behavior, often with a focus on behavior under natural conditions, and viewing behavior as an evolutionarily adaptive trait.

Given the context, the most fitting term is Comparative Psychology.

So, the completed sentence would be:

"Comparative Psychology is the study of differences and similarities in behaviour among men and also between man and animal."