Whichever the rider feels more comfortable on they both have there ups and downs
4 wheeled ATV.
Yes, bikes are safer than a skateboard because you can fall down when you do a flip over and you have to keep balance on a skateboard but you can hold on the handles and sit down on a bike.
By making sure it's in good operating condition. Good tires, brakes correctly adjusted ASO.Oh, wearing a helmet will make bicycling safer too.