P HELPPP ITS TIMES Read the excerpt from "The Great Molasses Flood of 1919."

Second, the molasses had been in the tank since July. This was a long time for molasses to be stored in a metal tank. During this time, the molasses began a chemical change. The molasses began making a gas called carbon dioxide. The tank was already too full. The carbon dioxide made matters worse. The gas pushed hard on the steel walls. The result was an explosion. The bottom of the tank blew out.

The cause-and-effect structure describes

a storage tank.
building with steel.
passing time.
a chemical reaction.

She took up a scalpel and slit the monkey's abdomen, making a slow and gentle cut, keeping the blade well away from her gloved fingers. the spleen was puffed up and tough, leathery, like a globe of smoked salami. she did not see any bloody lesions inside this monkey. she had expected that the monkey's interior would be a lake of blood, but no, this monkey looked all right, it had not bled into itself. if the animal had died of ebola, this was not a clear case. she opened up the intestine. there was no blood inside it. the gut looked okay. then she examined the stomach. there she found a ring of bleeding spots at the junction between the stomach and the small intestine. this could be a sign of ebola, but it was not a clear sign. it could also be a sign of simian fever, not ebola. therefore, she could not confirm the presence of ebola virus in this animal based on a visual inspection of the internal organs during necropsy.