Dual Argument Structure within an argument in LR-How common is it?

Butterflies and Lady Birds

Hey guys, I just listened to JY's explanation for Question 19 from PT 20 Section 1 and it looks like the argument had a dual argument structure within the passage. I wonder if this is something common in LSAT or just one time thing. I see it first time, but wanted to confirm. Thanks

https://7sage.com/lsat_explanations/lsat-20-section-1-question-19/