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K12 LibreTexts

16.5: Earth's History- Challenge 1

  • Page ID
    5586
  • 1. The inner planets are made primarily of ___.
    dense rock and metal
    2. ___ brings gas and dust together to form new stars.
    Gravity
    3. The planets formed because ___.
    clumps of material orbiting what would become the Sun continued to collide with each other due to gravity
    4. Earth formed ___ as the other planets.
    at about the same time
    5. Earth's early crust probably ___.
    recycled into the mantle because of vigorous convection
    6. Earth's interior separated into layers based on density through the process of ___.
    differentiation
    7. The ___ ratios of the Moon and Earth indicate that they originated in the same part of the solar system.
    oxygen isotope
    8. The Moon formed when ___.
    a Mars-sized asteroid hit Earth
    9. The material that came together to form the Moon was flung into space from ___.
    Earth
    10. Earth's first atmosphere was made up of ___.
    carbon dioxide, ammonia, hydrogen, and water vapor
    11. Oxygen appeared in Earth's atmosphere though ___.
    photosynthesis
    12. The ozone layer protects Earth's surface from ___.
    ultraviolet rays
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