[youtube]http://www.youtube.com/watch?v=N72kRbvXcvo[/youtube]

SYNOPSIS: This piece by BBC is a quick look into the reason for the dinosaurs’ extinction.  The “KT boundary” is a geologic line that signifies the moment in time when dinosaurs disappeared, and the presence of the mineral iridium suggests that the cause was a gigantic asteroid.

[popular value=4]

[difficulty value=4]

[transcript]what_really_killedthedinosaurs_transcript.html[/transcript]

Run Time: 3:03 minutes