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1. Describe DDT and summarize the history of the use and banning of DDT, including actions taken by the U.S. government. State t

igomit [66]

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.

4 0

4 years ago

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This sample is naturally occurring, inorganic, solid, has a square crystal structure, and a definite chemical composition (NaCl)

Alika [10]

Answer:

A Mineral is defined as an inorganic, naturally occurring, homogenoussolid, with a definite chemical composition, and ordered (crystalline) atomic structures.

Explanation:

Inorganic: Involving neither organic life nor the products created from or by organic life.

Naturally Occurring: Must be formed by natural processes, meaning a mineral cannot be manmade, manufactured, or created in a laboratory.

Homogeneous Solid: A mineral must be chemically and physically uniform down to the atomic level.

This homogeneity means that the mineral will have absolutely predictable physical properties

including hardness, density, and streak.

Definite Chemical Composition means that all occurrences of that mineral have a chemical

composition that varies within a specific limited range and the atoms that make up the mineral must

occur in specific ratios.

Ordered Atomic structure (Crystalline): The atoms in a mineral are arranged in a systematic and

repeating pattern. Glasses such as obsidian, which are disordered solids, liquids (e.g., water,

mercury), and gases (e.g., air) do not have a crystalline structure and are therefore not minerals.

5 0

2 years ago

A cell moves particle from a region of lesser concentration to a region of greater concentration by

disa [49]

Active transport (exocytosis, endocytosis, pumps, etc.)

4 0

3 years ago

Which of the following is the best reason that it might be difficult to predict an individual’s future health issues? a. Health

Dennis_Churaev [7]

Answer:

the answer is B.

Explanation:

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3 years ago

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Why do tropical rainforests have more species than all other biomes?

Katarina [22]

Answer:

Rainforests have an abundance of plants and animals for the following reasons: Climate: because rainforests are located in tropical regions, they receive a lot of sunlight. ... Since there is a lot of sunlight, there is a lot of energy in the rainforest. This energy is stored in plant vegetation, which is eaten by animals.

Explanation:

7 0

2 years ago