Many natural fruit juices with no added sugar contain more total sugar than fruit drinks which have had sugar added. Cow and breast milk contain a sugar called lactose, but this does not seem to cause as much tooth decay as sucrose.
We learn from the passage that _______.
1. fruit drinks with sugar added contain less total sugar than natural fruit juices
3. lactose can be found only in cow milk
2. natural fruit juices contain both lactose and sucrose
4. tooth decay can be caused by lactose