question: A rocket would only be able to fly low if its mass were
choices.text: higher lower
choices.label: A B
para: By using multiple stages, empty fuel containers could drop away. This reduced the mass of the rocket so that it could fly higher.
para_anno.effect_prop: altitude
para_anno.cause_dir_str: reduced
para_anno.effect_dir_str: higher
para_anno.cause_dir_sign: LESS
para_anno.effect_dir_sign: MORE
para_anno.cause_prop: mass of the rocket
question_anno.less_effect_dir: lower
question_anno.less_cause_prop: mass
question_anno.less_effect_prop: altitude
question_anno.less_cause_dir: altitude