Cell theory states that all the living organisms are made up of basic structural and functional units, cells. All cells divide and give rise to new cells. All the cells have similar chemical composition. The nuclei acid DNA present in the chromosomes helps in carrying hereditary information from generation to generation. So, in order to sustain life the cells must contain DNA either enclosed in the nucleus or freely floating in the cytoplasm.
Answer:
D. Anti-periplanar
Explanation:
In the <u>second step</u> of the intramolecular William Ether Synthesis mechanism (figure 1) we will have the attack of the negative charge of the oxygen to the carbon bond to the Br. At the same time the Br leaves, so a bond would be broken (the <u>C-Br</u> bond) and a bond would be formed (the <u>C-O</u> bond).
Now, this process can happen only if the <u>attack</u> and the <u>leaving group </u>has an anti configuration (figure 2). In an anti configuration the <u>nucleophile</u> and the <u>leaving group</u> would have <u>opposite directions</u>.
The earth's mantle will not change in the future because this region is safe from the intervention of human beings.
<h3>What happens in the Earth's mantle?</h3>
The transfer of heat and material in the mantle helps us to determine the landscape of Earth. Activity in the mantle moves the plate tectonics, that contributes to volcanoes, seafloor spreading, earthquakes, and building of mountains.
So we can conclude that the earth's mantle will not change in the future because this region is safe from the intervention of human beings.
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