The principles of can be learned and applied by people whose personal characteristics are quite different.

The correct word for the blank space is: adaptive selling, listening, and customer orientation.

Explanation:

Sales and customer service skills can be learned by different kinds of people. The keys for selling are being persuasive to create a need for the product being offered in the consumer and to adapt to them. When it comes to customer service, it is important to be a good listener to find out what the client needs so we can work on it. Customer service representatives must be patient as well to identify what the issue is when the customer cannot spot it.

it's called a focal point