Gases can be chemically active or inactive. this means that a gas either reacts or does not react when combined with other elements.
a definition of a noble gas is a gas that does not combine easily with other elements. an example of a noble gas is helium. a protective layer of helium prevents reactions with other elements such as oxygen.
helium has a very low density. it is used daily in weather balloons to carry instruments that record temperature, humidity, and pressure readings in the atmosphere.
people with breathing problems may be treated with a mixture of helium and oxygen. helium atoms are small and light. a helium-oxygen mixture can be pumped in and out of the lungs more easily than air. helium-oxygen mixtures are also used in breathing tanks of deep-sea divers.

using information from the passage, which statement is accurate?

1.a noble gas mixes well with other elements.
2.gases usually are chemically active.
3.helium is an example of a chemically inactive gas.
4.helium-oxygen mixtures are used in weather balloons.

1. read the following excerpt from franklin d. roosevelt's "fireside chat 19":

on the other side of the picture, we must learn also to know that guerilla warfare against the germans in, let us say serbia or norway, us; that a successful russian offensive against the germans us; and that british successes on land or sea in any part of the world strengthen our hands.

remember always that germany and italy, regardless of any formal declaration of war, consider themselves at war with the united states at this moment just as much as they consider themselves at war with britain or russia. and germany puts all the other republics of the americas into the same category of enemies. the people of our sister republics of this hemisphere can be honored by that fact.  

the true goal we seek is far above and beyond the ugly field of battle. when we resort to force, as now we must, we are determined that this force shall be directed toward ultimate good as well as against immediate evil. we americans are not destroyers — we are builders.

analyze the effectiveness of this excerpt. how does it function within the speech as a whole? how does the structure of the excerpt to convey the speech's purpose and key points? support your argument with evidence from the speech. (10 points)

c, his tragic flaw to cause his downfall