« previous next »

Author Question: The habitable zone is the area around a star where: A) planets with life have been found. B) ... (Read 65 times)

luvbio

  • Hero Member
  • *****
  • Posts: 623
on: Jul 27, 2018
The habitable zone is the area around a star where:
 
  A) planets with life have been found.
  B) human beings could live.
  C) the Greenhouse Effect is possible.
  D) a planet could have an atmosphere.
  E) temperatures are suitable for planets to have liquid water.

Question 2

Why does detection of abundant free oxygen in an atmosphere suggest life is present? Does its absence prove life could not be present?
 
  What will be an ideal response?


lkanara2

  • Sr. Member
  • ****
  • Posts: 329
Reply #1 on: Jul 27, 2018
Answer to Question 1

E

Answer to Question 2

Oxygen is highly reactive, and unless quickly replaced by photosynthesis, would soon disappear into surface rocks, as it has on Mars and Venus. However, life on Earth certainly evolved before it released the abundant present oxygen, and on other worlds, photosynthesis may not have evolved. Yet other forms of life may thrive using methane or hydrogen sulfide, all energy processes found here as well.


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question

luvbio

  • Hero Member
  • *****
  • Posts: 623
Reply #2 on: Jul 27, 2018
TY


lkanara2

  • Sr. Member
  • ****
  • Posts: 329
Reply #3 on: Jul 27, 2018
You're welcome


« previous next »
 

Did you know?

In 2012, nearly 24 milliion Americans, aged 12 and older, had abused an illicit drug, according to the National Institute on Drug Abuse (NIDA).

Did you know?

In the ancient and medieval periods, dysentery killed about ? of all babies before they reach 12 months of age. The disease was transferred through contaminated drinking water, because there was no way to adequately dispose of sewage, which contaminated the water.

Did you know?

Dogs have been used in studies to detect various cancers in human subjects. They have been trained to sniff breath samples from humans that were collected by having them breathe into special tubes. These people included 55 lung cancer patients, 31 breast cancer patients, and 83 cancer-free patients. The dogs detected 54 of the 55 lung cancer patients as having cancer, detected 28 of the 31 breast cancer patients, and gave only three false-positive results (detecting cancer in people who didn't have it).

Did you know?

Always store hazardous household chemicals in their original containers out of reach of children. These include bleach, paint, strippers and products containing turpentine, garden chemicals, oven cleaners, fondue fuels, nail polish, and nail polish remover.

Did you know?

The National Institutes of Health have supported research into acupuncture. This has shown that acupuncture significantly reduced pain associated with osteoarthritis of the knee, when used as a complement to conventional therapies.

European wildcat feeding its kittens, as illustrated in Brehm's Life of Animals European wildcat feeding its kittens, as illustrated in Brehm's Life of Animals
Pneumonia. This common lung inflammation may be caused by bacteria, viruses, or fungi and is often d Pneumonia. This common lung inflammation may be caused by bacteria, viruses, or fungi and is often d
A Rotating, Magnetized Neutron Star A Rotating, Magnetized Neutron Star
Mirror Neurons in Broca’s Area Mirror Neurons in Broca’s Area
Life cycle of acetylcholine (Ach): (1) Ach is released into the synaptic cleft; (2) Ach binds to ... Life cycle of acetylcholine (Ach): (1) Ach is released into the synaptic cleft; (2) Ach binds to ...
Flo Hyman was a 6 foot 5 inch star on the U.S. women’s volleyball team that won a silver medal in ... Flo Hyman was a 6 foot 5 inch star on the U.S. women’s volleyball team that won a silver medal in ...
Video: Structures that affect circulation - kidneys, blood volume and venous tone

For a complete list of videos, visit our video library