Question

Many psychologists believe that the facial expressions of human beings:

Answer 1

I believe the correct answer is facial expressions have strong biological ties.

Many psychologists believe that the facial expressions of human beings have strong biological ties. According to them, there are two types of facial expressions:
1. Voluntary, which are learned and socially influenced

2. Involuntary which are believed to be innate, just like few basic emotions such as fear.

Answer 2

There are no options in your question, but one way of finishing the sentence is saying that they "have a biological foundation and are influenced by our genes".

We think this because all humans interpret emotions similarly and because human babies start to smile when they are happy very early, before they could have learnt it.