DDT stands for dichloro-diphenyl-trichloroethane. The first kind of synthetic/artificial insecticides came into use in the 1940s. The earlier usage of DDT include: a) Killing of malarial vectors, b) Combatting Typhus and other insect borne human diseases, c) As a pest control in crops d) as a pest control in garden, live stock production and even at homes.
The negative impact of DDT could be felt for the first time when the pests that were earlier killed by use of DDT have now become pesticides resistant. In the 1950s in USA, the regulatory measures were adopted to reduce the usage of DDTs as its effects as a pesticides were no more long significant and also it was creating detrimental physical and psychological impacts on the human and environment.
It was in 1972 that the U.S. Environmental Protection Agency cancelled the order for banning the usage of DDT based on the adverse impact it produced on the environment, human and other life forms. Since then continuous studies are being conducted to analyse the impact of DDTs. In some later years it was established that DDT is the cause of producing tumors in liver.
Some of the common negative impacts produced by DDT as per the U.S. Department of Agriculture :
a) The non destructive nature – DDT can not be destroyed and thus it remains persistent in the atmosphere
b) It attacks the tissues of living organisms especially the animals and humans ( fatty tissue)
c) It can penetrate the atmosphere to deeper extent.
Now as per the current stuation, The use of DDT is controlled and other alternatives of pest control organisms is being deduced. As per the treaty of Stockholm Convention on POPs (Persistent organic pollutants) , usage of DDT for malarial control is justified but it puts a restrictive use of DDT as pesticides in other areas.
Answer;
An example of positive feedback loop is;
-When a pregnant woman begins to go into labor, the body sends hormones that increase the intensity of the labor contractions.
Explanation;
-Feedback loops are therefore the process whereby a change to the system results in an alarm which will trigger a certain result. The result will then either increase the change to the system or reduce it to bring the system back to normal.
-Feedback loops are important because they allow living organisms to maintain homeostasis (maintenance of internal environment of the body constant).
-A positive feedback loop occurs in nature when the product of a reaction leads to an increase in that reaction. It moves a system further away from the target of equilibrium, by amplifying the effects of a product or event and occurs when something needs to happen quickly.
Trace fossils represent things that were alive, it could be footprints, or bones.
I think this option fits best:
"<span>Evidence that animals were at some time in the area."</span>
Answer:
False
Explanation:
When energy is transferred from a producer to the consumer, only 10% of the energy from the <em>producer</em> is transferred to the <em>consumer</em>.
Hope this helps!
It was one Sunday morning. When me and my best friend ( NAME GOES HERE) switched lives we were playing a game and the game had a lot to do with holding hands
