Answer:
A and B are the answers.
Explanation:
Believe me I took a test a while ago with this question
<span>The specific heat of the metal is 0.5 cal/ (0C.g). This means the energy needed is 0.5 cal to raise the heat of 1 gram of metal by 1 degree C. Therefore, the energy needed to raise 100 g of the metal by 20 degrees C is:
0.5 * 20 * 100 = 1000 cal.
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Answer:
True
Explanation:
The Drosophila like the mammals possess X and Y chromosomes but as in males in which the XX is female and XY is male, the sex In Drosophila is not determined by the presence of Y chromosomes as a male determining factor are present on the autosomes.
However, the Y chromosome is important for males as they are involved in the formation of the sperms therefore the presence of Y is important. In the given question if the allele is present ion the Y chromosome which can reduce the size therefore the allele is passed on to the males only ans no females.
Thus, true is the correct answer.
the fly is female (Bridges 1921, 1925). Thus, XO Drosophila are sterile males. In flies, the Y chromosome is not involved in determining sex. Rather, it contains genes active in forming sperm in adults.
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.
