A stronger acid produces a greater concentration of ions than a weaker acid.  Milo is measuring acidity levels in his drink fridge. If his sprite is less acidic then his coke, which item has the greater concentration of ions coke or sprite?
coke

By using multiple stages, empty fuel containers could drop away. This reduced the mass of the rocket so that it could fly higher.  What happens when you lighten a rocket goes higher or falls down?
goes higher

Plug-in hybrids run for a longer time on electricity and so are less polluting than regular hybrids.  Kevin has a hybrid car and Steve has a large truck. Which car likely pollutes less hybrid or truck?
hybrid