Answer:
parallel and intersect at right angles
Explanation:
The roads in the urban areas tend to be very well organized and constructed. They tend to be parallel to each other, and also to intersect at right angels. The reason for this kind of building of the roads in the urban areas is to make the movement in the urban areas much easier and more efficient, mostly putting the accent on the traffic. It is a fact that the traffic is a big problem in the urban areas, so by constructing the roads in a well organized manner, the traffic jam eases up and the citizens can move more easily and quickly.
Answer – 3. A weakened form of a virus
When getting a vaccination, the substance which is injected into the body is a weakened form of a virus. This weakened from of the virus has the ability to arouse the body’s defense mechanism without causing an infection.
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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.
because they are both composed of 2 diffrent materials like how noses are made out of same material as a sharks "skin"
Phospholipids are the lipids are the main constituents of the cellular membrane. The phospholipids; sphingolipids, and phosphatidylcholine are the two foremost lipids of the membranes. Phospholipids help in maintaining the integrity and fluidity of the membranes.
