question: climate:warming:temperature
choices.label: A B C D
choices.text: survive:develop:sustain polar ice:melt:water level protection:environment:ecology greenhouse:gas:ozone
explanation:  "climate" "warming" can cause a rising "temperature", and the "climate" will be "warmer". "survival" and "development" belong to one category, and "survival" does not "develop". the "melting" of "polar ice" can cause the "water level" to rise, and the "polar ice" can "melt". the "environment" can be "protected". "gas" is a noun.
relation: climate warming R4.1
relation: survive develop R2.4
relation: polar ice melt R4.1
relation: environment protection R4.2