Watch the 4 videos and then write the summary for each one.
Video links:1. https://www.youtube.com/watch?v=apcWHKHf1fE&list=PL4640F5CA4FDF0352&index=5
- https://www.youtube.com/watch?v=cELkdAvaTWU&list=PL423DFFC24B54AE99&index=2
- https://www.youtube.com/watch?v=oJ8Jo3ASbx0&list=PL423DFFC24B54AE99&index=8
- https://www.youtube.com/watch?v=fRd5Qrtszhg&list=PL83F94A561326F885&index=4