In the following passage some words have been deleted. Fill in the blanks with the help of the alternatives given. Select the most appropriate option for each number.

Human activities are changing Earth's natural greenhouse1. ______. Burning fossil fuels like coal and oil puts 2. ______ carbon dioxide into our atmosphere. NASA has 3. ______ increase in the amount of carbon dioxide and some other greenhouse gases in 4. ______ atmosphere. Too much of these greenhouse gases can 5. ______ Earth's atmosphere to trap more and more heat. This causes Earth to warm up.