When will halley's comet be visible from earth again?

Which of the activities listed below could limit global warming by slowing the increase in atmospheric carbon dioxide levels? view available hint(s) select all that apply. a. replacing fossil fuels with nuclear energy b. burning vegetation to clear land for agriculture c. limiting soil erosion so organic matter takes longer to decompose d. choosing a fuel-efficient car, or bicycling to school or work e. using more electrical appliances and cars f. cutting down forests to build houses

Which of the following can scientists estimate geologic time? a. observing rock sequences b. radiometric dating c. comparing fossils d. all of these

Sink holes may eventually for to join a. wide valleys b. zone of aeration c. dripstones d. aquifer