 magnetic data evidence suggesting that Europa , Ganymede and Callisto have a liquid @-@ saltwater layer under the visible surface ; 
 magnetic data evidence suggesting that Europa , Ganymede and Callisto <a href='got' title='1'><mark>have</mark></a> a liquid @-@ saltwater layer under the visible surface ; 
Magnetic data evidence suggesting dat Europa , Ganymede and Callisto got a liquid @-@ saltwater layer under da visible surface ;