Problem: As for engravings, Durer's work was restricted to portraits and illustrations for his treatise. The portraits include Cardinal-Elector Albert of Mainz; Frederick the Wise, elector of Saxony; the humanist scholar Willibald Pirckheimer; Philipp Melanchthon, and Erasmus of Rotterdam. For those of the Cardinal, Melanchthon, and Durer's final major work, a drawn portrait of the Nuremberg patrician Ulrich Starck, Durer depicted the sitters in profile, perhaps reflecting a more mathematical approach. Despite complaining of his lack of a formal classical education, Durer was greatly interested in intellectual matters and learned much from his boyhood friend Willibald Pirckheimer, whom he no doubt consulted on the content of many of his images. He also derived great satisfaction from his friendships and correspondence with Erasmus and other scholars. Durer succeeded in producing two books during his lifetime. "The Four Books on Measurement" were published at Nuremberg in 1525 and was the first book for adults on mathematics in German, as well as being cited later by Galileo and Kepler. The other, a work on city fortifications, was published in 1527. "The Four Books on Human Proportion" were published posthumously, shortly after his death in 1528.

Question: "Who engraved the portrait of Cardinal-Elector Albert of Mainz?"

Answer: "Frederick the Wise"
Answer: no

Problem: "What goes up must come down." You have probably heard that statement before. At one time this statement was true, but no longer. Since the 1960s, we have sent many spacecraft into space. Some are still traveling away from Earth. So it is possible to overcome gravity. Do you need a giant rocket to overcome gravity? No, you actually overcome gravity every day. Think about when you climb a set of stairs. When you do, you are overcoming gravity. What if you jump on a trampoline? You are overcoming gravity for a few seconds. Everyone can overcome gravity. You just need to apply a force larger than gravity. Think about that the next time you jump into the air. You are overcoming gravity for a brief second. Enjoy it while it lasts. Eventually, gravity will win the battle.

Question: "What objects are still traveling away from Earth?"

Answer: "Spaceships"
Answer: yes

Problem: Surely, you have noticed the tall poles along the roadside. Do you know what is on top of those poles? Thats right, wires that carry electric current. These wires carry electric current to your home. But what is electric current? Electric current is actually the flow of electrons. You may recall, an electron is the outer-most particle in an atom. They have a negative charge. Electricity is the continuous flow of these particles. Electrons are able to move through wires. Their speed can even be measured. The SI unit for electric current (or speed) is the ampere (A). Ampere is often shortened to amp. Electric current may flow in just one direction, or it may keep reversing direction. Direct current (DC) flows in only one direction. Direct current is what is used in devices like flashlights. Alternating current (AC) flows in two directions. This is the type of current that flows into your home through wires.

Question: "How is alternating current different from direct current?"

Answer: "Direct current flows in one direction. Alternating current flows in two directions"
Answer:
yes