This is a pedigree for a family in which several individuals develop a neurodegenerative disease late in life. If individual A has children with an unaffected woman, what is the probability that their first child will be affected?

I believe it's one half.

Explanation:

I can't see the pedigree, but depending if the disease is recessive or dominantly expressed it will show how the disease will affect offspring. But overall, I think the chances would probably be 50% because each parent gives half of their genes to their offspring, meaning there is about a 50/50 chance for the disease to affect the child if only one of the parents in affected. (It still depends if the disease is recessive, if it is, then the person would probably be a carrier). Hope this helps!

it is a learned trait

explanation: