Allan sat down at his desk and pulled the chair in close. Opening a side drawer, he took out a piece of paper and his inkpot. After filling his pen, Allan looked at his paper in the orange glow from the lantern set back in the desk's right-hand corner. His pen cast a forbidding line of shadow slanting across the page, echoing the inky darkness crouching in the edges of the lantern's struggling glow. The only other illumination came from a lurid moonlight filtered through thin branches and clouds, casting its bone-pale glow onto the pine floorboards. Allan unfolded another page, this one crowded with ranks of letters in tight formation from left to right. The lines of letters stepped into their divisions, in the shape of a story's outline: the loose, dry skeleton of a tale lay exposed beneath their feet, awaiting tendons, muscle and blushing skin. Allan reviewed the troops, all prepared to disembark, their task to form the tale of a young man returning home from Life Abroad to find his childhood friend a bride to-be, thus upsetting the apple cart of his life's plan, clarified of course by his very time away from her he loved best. Although the concept was a simple one, Allan thought it had potential. Besides, the public liked a good, simple romance. Perhaps this will be more saleable, he thought and began to write. They gazed at each other, lost in the rapture of love based so deeply within their hearts that they had never seen it before. "What about Roger?" she asked, knowing that the answer no longer mattered.

What are the two light sources Allan is using to write?

Earths magnetic field helps protect Earth and its organisms. It protects us from harmful particles given off by the sun. Most of the particles are attracted to the north and south magnetic poles. This is where Earths magnetic field is strongest. This is also where relatively few organisms live. Another benefit of Earths magnetic field is its use for navigation. People use compasses to detect Earths magnetic north pole. Knowing this helps them tell direction. Many animals have natural 'compasses' that work just as well. Birds like the garden warbler in Figure 1.36 use Earths magnetic field. They use it to guide their annual migrations. Recent research suggests that warblers and other migrating birds have structures in their eyes. These structures let them see Earths magnetic field as a visual pattern.

According to this passage, what protects the organisms of Earth from harmful particles given off by the sun?

Fossils give clues about major geological events. Fossils can also give clues about past climates. Fossils of ocean animals on the top of a mountain? Ocean animals have been found on the Earths tallest mountain. Its hard to believe, but it is true. These fossils were found at the top of Mt. Everest. Mt. Everest is the highest mountain on Earth. These fossils showed that this entire area was once at the bottom of a sea. It can only mean that Mt. Everest was uplifted. In fact, the entire Himalaya mountain range was raised. It was forced up from the collision of two continents. Fossils of plants are found in Antarctica. Now, Antarctica is almost completely covered with ice. Plants do not grow in Antarctica. According to fossils, they once did. This means that Antarctica was once much warmer than it is now. These fossils tell us about Antarcticas past climate.
What does the fact that fossils have been found on the top of Antarctica?