Homework Help Forum: Biology

Posted by Anne on Friday, October 30, 2009 at 10:35pm.

What are two autotrphs that don't use sunlight? How might these organisms provide clues to exterrestrial life?

• Writing I - Maria, Friday, October 30, 2009 at 10:46pm

  Label each sentence below. Use S for simple, CD for compound, CX for complex, and CD-CX for compound-complex. 1. Do you know the theory of black holes? 2. Objects in space have gravitational pull, so smaller objects are attracted to larger object. 3. Throw a rock into the air, and it falls to earth when gravity pulls the rock down. 4. Imagine throwing a rock so far and fast that it escapes the earth's gravitational pull. 5. The exact speed necessary to escape gravitational pull is called escape velocity. 6. Escape velocity and age contribute to the creation of black holes. 7. A larger star grows old and can't withstand the force of its own gravity, so it collapses. 8. The star collapses to a fraction of its former size, but mass and gravity remain the same. 9. A concentrated field of gravity is created because the forces of mass and gravity stay strong despite the collapse, and a black hole is formed. 10. With an escape velocity beyond light speed, a black hole prevents light from escaping and this gives the black hole its name. 11. Replacing the name "frozen star", John Archibald Wheeler coined the term "black hole." 12. You cannot travel at such speeds. 13. The existence of black holes is difficult to prove, but scientists continue trying.

  
  

• Biology - Anonymous, Friday, October 30, 2009 at 11:41pm

  Photoautotrophs use energy from sunlight to convert chemicals into organic components. Chemoautotrophs use other forms of energy. Tube worms in deep sea thermal vents are an example.

  
  

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