This topic contains a solution. Click here to go to the answer

Author Question: What methods are used to test chemicals for their potential to cause cancer? What will be an ... (Read 32 times)

dollx

  • Hero Member
  • *****
  • Posts: 558
What methods are used to test chemicals for their potential to cause cancer?
 
  What will be an ideal response?

Question 2

What is biodiversity? What do scientists need to know to calculate it for a habitat?
 
  What will be an ideal response?



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

nekcihc358

  • Sr. Member
  • ****
  • Posts: 327
Answer to Question 1

We do not want to wait 20 years to find out that a new food additive causes cancer, so we turn to animal testing to find out now what might happen in the future. A test involving several hundred animals (usually mice) takes about 3 years and costs more than 250,000 . If a significant number of the animals develop tumors after having been feed the substance being tested, then the substance is either a possible or probable human carcinogen, depending on the strength of the results. Although there are obvious differences between rodents and humans, all chemicals shown by epidemiological studies to be human carcinogens are also carcinogenic to test animals, suggesting that animal tests have some predictive value for humans. In the past, chemical manufacturers that were interested in assessing the safety of pesticides (in order to have their products approved for use) paid human subjects to test the products. Such tests are far less expensive than the usual animal testing. (Volunteers may be paid only a few hundred dollars; mice apparently charge much higher fees) A National Academy of Sciences panel addressed this topic in 1998, stating that the use of human volunteers to facilitate the interests of industry or of agriculture' is unjustifiable. The EPA agreed and banned any use of such tests. However, recently the Bush administration, responding to requests from manufacturers, pressed the EPA to reevaluate its policy and allow human testing. A new rule from EPA forbids such testing on children and pregnant women (but allows it for others), satisfying the pesticide manufacturers. Another source of information is the chemical process itself: What are its physical and chemical properties, and what mode of action might the chemical process take in inducing cancer? Hazard assessment takes a weight-of-evidence' approach to determining the carcinogenic potential of a chemical of process. Standard descriptors are used in its conclusions, such as likely to be carcinogenic to humans.' In the end hazard assessment tells us what may be a problem.

Answer to Question 2

Biodiversity is the result of speciation and extinction occurring over time, and the result of these two processes has been the gradual increase in the number of species. No one knows how much biodiversity exists. Estimates range widely, and the upper-limit estimates keep rising. Groups especially rich in species are the flowering plants (270,000 species) and the insects (950,000 species), but even less diverse groups, such as birds or ferns, are rich with species that are unknown to most people.




dollx

  • Member
  • Posts: 558
Reply 2 on: Jul 15, 2018
Great answer, keep it coming :)


deja

  • Member
  • Posts: 332
Reply 3 on: Yesterday
Wow, this really help

 

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.

Did you know?

There can actually be a 25-hour time difference between certain locations in the world. The International Date Line passes between the islands of Samoa and American Samoa. It is not a straight line, but "zig-zags" around various island chains. Therefore, Samoa and nearby islands have one date, while American Samoa and nearby islands are one day behind. Daylight saving time is used in some islands, but not in others—further shifting the hours out of sync with natural time.

Did you know?

The largest baby ever born weighed more than 23 pounds but died just 11 hours after his birth in 1879. The largest surviving baby was born in October 2009 in Sumatra, Indonesia, and weighed an astounding 19.2 pounds at birth.

Did you know?

Automated pill dispensing systems have alarms to alert patients when the correct dosing time has arrived. Most systems work with many varieties of medications, so patients who are taking a variety of drugs can still be in control of their dose regimen.

Did you know?

When taking monoamine oxidase inhibitors, people should avoid a variety of foods, which include alcoholic beverages, bean curd, broad (fava) bean pods, cheese, fish, ginseng, protein extracts, meat, sauerkraut, shrimp paste, soups, and yeast.

For a complete list of videos, visit our video library