ELI5 Asteroids - why does NASA want a piece of one?

Explain asteroids vs comets vs meteoroids? An asteroid sample from the asteroid Bennu is now on its way back to earth (due in 2023) - why does NASA want to catch an asteroid and send samples back to earth? Did a meteorite kill the dinosaurs?   ... We explain like i'm five!   Thank you to the r/explainlikeimfive community as always and in particular the following users whose questions and comments formed the basis of this discussion: neil1859, ultimateagentm, greenlandys, wayfareandwanderlust & mq7cqzsbk To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Send us an e-mail: [email protected]