Questions 16-20 refer to the following passage. Passage I On Nov. 27, the Big Island of Hawaii's Mauna Loa volcano — the largest active volcano in the world — erupted for the first time in 38 years. This eruption was very special because Mauna Loa historically erupts very frequently, every six years on average. It took me two attempts to finally get a glimpse of the eruption. My first attempt on Dec. 3 was __(16)__ because of low visibility, caused by clouds covering the volcano, and a lack of parking availability on side roads. Some of the side roads were temporarily converted to one-way streets to __(17)__ traffic away from the busy, but orderly, main highway near the volcano summit. My second attempt was successful. I departed from my hotel in the town of Hilo at 2 a.m. and arrived at the nearest open side road, as close to the eruption site as possible. The sky was clear, and the beautiful and glowing reddish volcano plumes were __(18)__ as far as Hilo. Volcanic eruptions can either be explosive or effusive. Unlike explosive volcanoes that __(19)__ ash and magma up into the atmosphere, most Hawaiian eruptions — including the Mauna Loa — are known for their nonexplosive nature. This means they have less direct human impacts in the form of injuries and __(20)__. 16.