Scientists have found no major epigenetic differences in astronaut ________, who spent a year in space aboard the International Space Station, and his twin brother, Mark Kelly, who remained on Earth.

Scientists have found no major epigenetic differences in astronaut ___

1.	Scientists have found no major epigenetic differences in astronaut ________, who spent a year in space aboard the International Space Station, and his twin brother, Mark Kelly, who remained on Earth.
A.	Chris Kelly
B.	Scott Kelly
C.	Timothy Kelly
D.	Yuri Kelly
E.	Oleg Kelly
Answer» C. Timothy Kelly