A (carbon tax) can be international.Logical formLearned from18 sentences. (Carbon dioxide levels) can be high.Logical formLearned from18 sentences. (Carbon sources) can be organic.Logical formLearned from18 sentences. (Carbon dioxide) may undergo a disposal.Logical formLearned from18 sentences. (Carbon values) can be organic.Logical formLearned from18 sentences. Properties can be constituted-of-or-filled-with (carbon nanotubes).Logical formLearned from18 sentences. (Carbon nanotubes) can be metallic.Logical formLearned from18 sentences. A price can be for (carbon emissions).Logical formLearned from18 sentences. Carbon may undergo a buildup.Logical formLearned from18 sentences. A release can be constituted-of-or-filled-with carbon.Logical formLearned from18 sentences. A (carbon dioxide) may be released into air.Logical formLearned from18 sentences. (Fuel efficiency) can be with carbon.Logical formLearned from18 sentences. Companies may emit (carbon dioxide).Logical formLearned from18 sentences. (Carbon dioxide) may be absorbed by forests.Logical formLearned from18 sentences. Traces can be constituted-of-or-filled-with carbon.Logical formLearned from18 sentences.