Answer:
Uncle Axel is a kind man who does not share the Waknukian extreme beliefs, he is reasonable about issues that the authorities consider as Offences.
He has an open mind regarding his world and the rest of the world beyond the Labradors, and is concerned with the actual origin of things.
However he is also shrewd enough to keep his beliefs to himself.
These traits of his helps to develop and reinforce the idea of necessary secrecy for David (the protagonist) and others, the support his character gives David and the others enables them to live for many years without detection.
He indirectly encourages David to explore the world and follow his dreams when he gets the chance. His insistence that David helps to keep others like him safe contributes to the climax of the story, in that the group's effort to keep one of them safe lead to their being detected and brought under suspicion.
Explanation:
In <em>The Chrysalids</em> Uncle Axel is David's uncle, he is a kind and reasonable man who keeps an open mind and does not share the extreme religious belief of his people.
His character personality and support for David is the catalyst fro most of David's actions in the story, which contribute to the development of and complication of the plot.