4. A thick layer of volcanic ash can be heavy enough to collapse the roofs of buildings because ash a. is solid. b. cannot be blown by winds. becomes heavier as it cools. d. consists of tiny fragments of rocks that becomes heavy as they pile up. C. а. 5. Which of the following is an active volcano in the Philippines? Apo in Davao b. Bud Datu in Sulu C. Isarog in Camarines Sur d. Kanlaon in Negros Oriental the following cuestions briefly