Simplify the following text for a Grade 9 native English-speaking person.
Original: Throughout much of the newtâ s range , the common garter snake ( Thamnophis sirtalis ) has been observed to exhibit resistance to the tetrodotoxin produced in its skin .
Simplified: Throughout much of the newtâ s range , the common garter snake ( Thamnophis sirtalis ) is resistant to the newt 's toxin .