Great for an Emergency sub plan! The documentary by National Geographic,
(Genetic Mutations - Hidden Secret) is relative to the 8th grade genetics unit, its engaging and its on YouTube. https://www.youtube.com/watch?v=Kk2yHeRoc9w
Its also 48 minutes long which is perfect for a 55 minute class period. The questions are in order and they're time stamped so you know when the answers are coming up.
Answer key included