DDT (Dichloro-diphenyl Trichloroethane) is a biocide. Biocides is the term that is broadly used to refer bactericides, fungicides, nematicides, insecticides, rodenticides and weedicides. A long term use of DDT can have favourable effect by resulting in complete eradication of the potential pests and invaders from an agricultural field. But the use of DDT for a long time has showed dangerous outcomes in the form of Biomagnification that resulted in tremendous decrease in bird population.
Explanation:
Biomagnification is defined as a gradual increase in concentration of a substance in successive trophic levels of a food chain.
Biomagnification of DDT interfered with the egg-shell formation and the thin shelled eggs broke at a premature stage. Thus , the bird population decreased significantly.
A taxonomist is someone who classifies animals, plants, and other organisms into their respective kingdoms, allowing the earth to be separated into different types of things. The conservation of habitats is one of the most important factors to a taxonomist because organisms are found only in specific areas/habitats. If these areas were to be destroyed, it is possible that unclassified species could be destroyed along with it, causing the taxonomist to be unable to discover them and share them with the world.
Explanation:
The real magnitude of this challenge can perhaps be best judged by considering the structural and functional complexity of the human brain and the bewildering complexity of human behavior. The human brain is thought to be composed of about a hundred billion (1011) nerve cells and about 10 to 50 times that number of supporting elements or glial cells. Some nerve cells have relatively few connections with other neurons or with such effector organs as muscles or glands, but the great majority receive connections from thousands of other cells and may themselves connect with several hundred other neurons. This means that at a fairly conservative estimate the total number of functional connections (known as synapses) within the human brain is on the order of a hundred trillion (1014). But what is most important is that these connections are not random or indiscriminate:
They constitute the essential "wiring" of the nervous system on which the extraordinarily precise functioning of the brain depends. We owe to the great neuroanatomists of the last century, and especially to Ramón y Cajal, the brilliant insight that cells with basically similar properties are able to produce very different actions because they are connected to each other and to the sensory receptors and effector organs of the body in different ways. One major objective of modern neuroscience is therefore to unravel the patterns of connections within the nervous system—in a word, to map the brain.
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Firstly the question is incomplete as an option is not there.
Why do the number of organisms in a group change from the first step to the last step of a dichotomous key?
a. The number of organisms decreases because the number of common characteristics of the organisms in a group increases.
b. The number of organisms increases because the number of common characteristics of the organisms in a group increases.
c. The number of organisms is cut in half because the number of common characteristics of the organisms in a group decreases by half in the last step.
d. The number of organisms stays the same because the number of common characteristics of the organisms in a group decreases by half in the last step.
The correct answer is B. The number of organisms increases because the number of common characteristics of the organisms in a group increases.
The most common key for the identification of organisms is a dichotomous key, the number of organisms in a group change from the first step to the last step of a dichotomous key as the no. of organisms increases and forms several groups of species and genus.
<h3>What is the use of the dichotomous key?</h3>
The use of dichotomous keys are :
- contrasting characters
- dividing organisms
- eliminating .
Hence concluded that the dichotomous key has a number of organisms increases because the number of common characteristics of the organisms in a group increases.
To learn more about dichotomous keys refer to the link :
brainly.com/question/1281957
