Simplify the following text for a Grade 8 native English-speaking person.
Original: Using poisoned arrows , Artemis killed Niobe 's daughters and Apollo killed Niobe 's sons , while they practiced athletics , with the last to die begging for their lives .
Simplified: Artemis killed Niobe 's daughters and Apollo killed Niobe 's sons as they practiced athletics , with the last begging for his life .