You are given a paragraph, a question and some answer options (associated with "A", "B", "C", "D", etc.) You need to list all the correct answer options with their associated letters (e.g. "A" can be a valid answer). Note that sometimes, more than one option can answer the question correctly and completely. In those cases, please generate all such options separated by a comma (e.g. "A, B" is a valid answer). Do not generate anything else apart from one or more of the following characters: 'A', 'B, 'C', 'D', etc.

Paragraph- Sent 1: Rivers flowing over gentle slopes move more slowly.
Sent 2: They move much more slowly than a mountain stream.
Sent 3: These slow moving streams create different types of features than mountain streams.
Sent 4: Slow moving water erodes the sides of their channels more than the bottom.
Sent 5: Also, large curves in the stream form.
Sent 6: These curves are called meanders.
Sent 7: Meanders are caused by erosion and deposition.
Sent 8: Remember, faster moving water causes erosion more quickly.
Sent 9: Slower moving water erodes material more slowly.
Sent 10: If water is moving slowly enough, the sediment being carried may settle out.
Sent 11: This settling out, or dropping off, of sediment is deposition.
Sent 12: The curves are called meanders because they slowly wander over the land.
Sent 13: As meanders erode from side to side, they create a floodplain.
Sent 14: This is a broad, flat area on both sides of a river.
Sent 15: Eventually, a meander may become cut off from the rest of the river.
Sent 16: This forms an oxbow lake. 
Question: What are the two processes that form large curves in streams? (A) Meanders and floodplains (B) Erosion and deposition (C) Slow moving streams create different types of features than mountain streams, Slow moving water erodes the sides of their channels more than the bottom (D) River water flowing over gentle slopes, forming of meanders.
B, C.

Paragraph- Sent 1: Gravitational Potential Energy is affected by position.
Sent 2: Like the leaves on trees, anything that is raised up has the potential to fall.
Sent 3: It has potential energy.
Sent 4: You can see examples of people with gravitational potential energy in 1.5 Figure below.
Sent 5: Gravitational potential energy depends on two things.
Sent 6: It depends on its weight, because a large falling rock can do more damage than a leaf falling from a tree.
Sent 7: It also depends on its height above the ground.
Sent 8: Like the skateboarder, the higher the ramp, the faster he will be going when he reaches the bottom.
Sent 9: Like all energy, gravitational potential energy has the ability to do work.
Sent 10: In this case, weight has the potential to deliver a force.
Sent 11: More important for us is that it has the ability to cause change.
Sent 12: What kind of change you may ask?
Sent 13: Gravitational potential energy has the ability to cause motion. 
Question: What is the most important change gravitational potential energy can have? (A) The ability to cause motion (B) Motion (C) Friction (D) Deliver make skateboarders move.
A, B.

Paragraph- Sent 1: Hundreds of thousands of years before China was to become the world's longest-running civilization, the prologue was enacted by means of the flicker of a carefully tended fire.
Sent 2: Peking Man, a forebear of Homo sapiens, achieved a mastery of fire.
Sent 3: We might call it the first Chinese invention.
Sent 4: Not that he devised flint and steel, matches, or any other way of creating fire.
Sent 5: Peking Man simply learned how to capture flame, perhaps from a forest fire, and keep it alight.
Sent 6: He thus enjoyed two revolutionary luxuries: light and heat.
Sent 7: Technologically and sociologically, it was a phenomenal breakthrough: with fire, communities could live year 'round in one cave, in which cooking and even smelting could be pursued.
Sent 8: And so, by 600,000 b.c., about 50 km (31 miles) southwest of present-day Beijing, the ancestors of mankind were ready to settle down.
Sent 9: Several hundred thousand years later, when Marco Polo reached the capital of China, he was astonished by a further development in fire technology.
Sent 10: The Chinese, he announced, used black stones dug out of mountains as fuel.
Sent 11: Europeans did not yet have a word for "coal," nor had they discovered a use for it.
Sent 12: The First Dynasty The confluence of mythology and history in China took place around 4,000 years ago during what is referred to as the Xia (Hsia) Dynasty.
Sent 13: This was still the Stone Age, but the people are thought to have made silk from thread produced by the worms they cultivated on the leaves of their mulberry trees.
Sent 14: And written language (which evolved as early as 4,500 to 5,000 years ago) was already in use, originally by oracles and then by official scribes — China's first scholars.
Sent 15: During the second of the quasi-legendary dynasties, the Shang (from about the 16th to 11th centuries b.c.), the Chinese developed an interest in art.
Sent 16: Careful geometric designs as well as dragon and bird motifs adorned bowls and implements.
Sent 17: And with the arrival of the Bronze Age, the Chinese created bronze vessels of such beauty and originality that, until modern times, archaeologists refused to believe they were cast 3,000 years ago.
Sent 18: The Shang Dynasty gave rise to the concept of one Chinese nation under one government. 
Question: The first Chinese invention involved a master of what subject? (A) Civilization (B) Art (C) Silk trade (D) Fire (E) Capturing fire.

D, E.

