Student or Learner
This seems to be a no-brainer, but there's a little doubt left in me. This underlined defintely seems a predictive(or presumed) conditional of the past, but it also seems like a counterfactual conditional of the past, which would need "they would be able to.." in the main clause. So there's a high chance that it is presumption. What do you think?
130)Have you ever tasted your tears? If so, you will know they taste salty...Emotional tears generally contain more salt than reaction tears, so they taste saltier....Less water makes even saltier tears. So tears of anger taste saltier than tears of other emotions. Therefore, if experts tested your various tears, they might be able to guess how you felt when you cried.
It falls into the traditional second conditional category. Hypothetically, If they did that now (counterfactual) or in the future (possible) they would/might be able to guess ...