What causes cystic fibrosis?

Hi the picture will help you better understand that explanation. :)

Explanation:

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***‘CF stands for Cystic fibrosis‘***

It mostly happens when your parents have them. (It passes on... so you get it from your parents.)

(Answer to your question) => People who have that, it’s hard for them to breathe. Cystic fibrosis happens from changes from CFTR. Just in case if you think you have them, but you want to make sure... than you should do a Blood test, DNA test, and Sweat test. If they find out they have that, than they should try to take care of them self. But the only thing is... there is no cure for this disease. :( below is a picture...

By:✨RobloxYt✨

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

the answer would be..

b. sucking