Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions. Just two months after the flight of Apollo 10, the Apollo 11 astronauts made their historic landing on the surface of the Moon. This momentous trip for humanity also provided scientists with an abundance of material for study; from rock and soil samples brought back from the Moon, scientists have been able to determine much about the composition of the Moon ...

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

Just two months after the flight of Apollo 10, the Apollo 11 astronauts made their historic landing on the surface of the Moon. This momentous trip for humanity also provided scientists with an abundance of material for study; from rock and soil samples brought back from the Moon, scientists have been able to determine much about the composition of the Moon (as well as to draw) inferences about the development of the Moon from its composition.

The Moon soil that came back on Apollo 11 contains small bits of rock and glass which were probably ground from larger rocks when meteors impacted with the surface of the Moon. The bits of glass are spherical in shape and constitute approximately half of the Moon soil. Scientists found no trace of animal or plant life in this soil.

In addition to the Moon soil, astronauts gathered two basic types of rocks from the surface of the Moon: Basalt and breccia. Basalt is a cooled and hardened volcanic lava common to the Earth. Since basalt is formed under extremely high temperatures, the presence of this type of rock is an indication that the temperature of the Moon was once extremely hot. Breccia, the other kind of rock brought back by the astronauts, was formed during the impact of falling objects on the surface of the Moon. It consists of small pieces of rock compressed together by the force of impact. Gases such as hydrogen and helium were found in some of the rocks, and scientists believe that these gases were carried to the Moon by the solar wind, the streams of gases that are constantly emitted by the Sun.