Without them, scooping would be very difficult. Usually, the higher the butterfat, the richer and smoother the ice cream. Frozen yogurt uses yogurt which is fermented milk. Yogurts with higher fat levels make creamier frozen yogurts. Usually this is sugar.
Sugar also helps to keep the ice cream from becoming a solid block of ice.
Because water that has sugar dissolved in it has a freezing point below 32 degrees, not all the water present in the ice cream freezes. Stabilizers - These are added to protect the ice cream. Since ice cream can often thaw during transport and then be refrozen at the store, stabilizers keep the ice cream from getting ice lumps. Look carefully at it- both its texture and color. Part of tasting is what it looks like.