Simplify the following text for a Grade 13 native English-speaking person.
Original: Studies in the 1990s at Boxgrove , in which a butcher attempted to cut up a carcass with a hand axe , revealed that the hand axe was perfect for getting at the bone marrow , which is high in protein and vitamins and thus was likely highly prized as a food source .
Simplified: Studies in the 1990s at Boxgrove , in which a butcher attempted to cut up a carcass with a hand axe , showed that the hand axe was perfect for getting at the bone marrow , which is high in protein and vitamins and thus was highly prized as a food source .