Le mot "pas"

Question

J'ai appris beaucoup de cet exercise. Pourquoi il n'y a pas le mot "pas" dans la phrase .....qu'ils ne soient nés en captivité...?  Merci.

Accepted Answer

Janet, 
The ' ne ' here is the ' ne explétif ', formal and optional. It does not change the meaning of the phrase.  An English translation would be ' unless they are/were born in captivity '. 
Its use here is triggered by ' à moins que... '. 
Have a look at the links below :
 https://progress.lawlessfrench.com/revision/grammar/how-to-say-unless-you-do-a-moins-que-ne-expletif-subjonctif 
https://www.lawlessfrench.com/grammar/ne-expletif/

Answer

Thank you for the explanation!