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.

Name two benefits of Earths magnetic field.

To say her face fell would do a disservice to Tasha and to literature. (Allow me my self-indulgences as you would those of a dying man -- when I convince my mindsmith to permit the wipe, there will be another Bernardo Flynn, one who knows no more of Tasha Cortez or Vega IV than he reads here.) Her brows drew together, creasing the lovely, caramel-colored skin around her eyes and showing the pattern for an old woman's wrinkles on her forehead. Her lower lip (a trifle too narrow for her face, perhaps her only physical flaw) thrust forward slightly as she started to speak. She caught herself, slid her jaw infinitesimally back into place, and said, "You don't like it?" I laughed. What could I do? I clapped her shoulder to show I was not laughing at her. "Like it? I hate it, despise it, abhor it! It's gaudy, graceless, pretentious -- That house is an affront to taste and intelligence. I should buy it to raze it, but I am not so kind-hearted. I might, however, rent it." I think she only heard the last words of my speech. "You will?" "It amuses me. Show me around, and then I shall decide." "Of course, Senor Flynn." "And stop calling me 'senor'. Not even Los Mundos is so polite. Call me Bernardo."

What does Bernardo need to do before he can decide whether to rent the house?

He repeatedly calls on his followers to embrace martyrdom since "The walls of oppression and humiliation cannot be demolished except in a rain of bullets." For those yearning for a lost sense of order in an older, more tranquil world, he offers his "Caliphate" as an imagined alternative to today's uncertainty. For others, he offers simplistic conspiracies to explain their world. Bin Laden also relies heavily on the Egyptian writer Sayyid Qutb. A member of the Muslim Brotherhood executed in 1966 on charges of attempting to overthrow the government, Qutb mixed Islamic scholarship with a very superficial acquaintance with Western history and thought. Sent by the Egyptian government to study in the United States in the late 1940s, Qutb returned with an enormous loathing of Western society and history. He dismissed Western achievements as entirely material, arguing that Western society possesses "nothing that will satisfy its own conscience and justify its existence." Three basic themes emerge from Qutb's writings. First, he claimed that the world was beset with barbarism, licentiousness, and unbelief (a condition he called jahiliyya, the religious term for the period of ignorance prior to the revelations given to the Prophet Mohammed). Qutb argued that humans can choose only between Islam and jahiliyya. Second, he warned that more people, including Muslims, were attracted to jahiliyya and its material comforts than to his view of Islam; jahiliyya could therefore triumph over Islam. Third, no middle ground exists in what Qutb conceived as a struggle between God and Satan. All Muslims-as he defined them-therefore must take up arms in this fight. Any Muslim who rejects his ideas is just one more nonbeliever worthy of destruction. Bin Laden shares Qutb's stark view, permitting him and his followers to rationalize even unprovoked mass murder as righteous defense of an embattled faith. Many Americans have wondered, "Why do 'they' hate us?" Some also ask, "What can we do to stop these attacks?" Bin Laden and al Qaeda have given answers to both these questions.
Who offers simplistic conspiracies to explain their world