Chemical and gaseous exchange takes place only across capillary walls
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Answer:
D. Sulfur
Explanation:
Electrons are filled in shells. Oxygen has a total of 8 electrons while sulfur has a total of 16 electrons. Out of the total eight electrons, the first shell has two electrons while six electrons are filled in the “s and p” orbits of the second shell giving the outer shell a configuration of "2s2, 2p4".
Likewise, out of the total 16 electrons of sulfur, the last 6 electrons are filled in "s" and "p" orbits of the third shell. Sulfur has a total of six electrons in its outer most shell "3s² 3p⁴". Since the electrons present in the outer most shell are available for chemical reactions and determine the chemical nature of the atom, oxygen and sulfur should exhibit the same chemical properties.
A virus<span> is a small </span>infectious agent<span> that </span>replicates<span> only inside the living </span>cells<span> of other </span>organisms<span>. Viruses can infect all types of </span>life forms<span>, from </span>animals<span> and </span>plants<span> to </span>microorganisms<span>, including </span>bacteria<span> and </span><span>archaea
</span>While not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles. These viral particles<span>, also known as </span>virions<span>, consist of two or three parts: (i) the </span>genetic material<span> made from either </span>DNA<span> or </span>RNA<span>, long </span>molecules<span> that carry genetic information; (ii) a </span>protein<span> coat, called the </span>capsid<span>, which surrounds and protects the genetic material; and in some cases (iii) an </span>envelope<span> of </span>lipids<span> that surrounds the protein coat when they are outside a cell. The shapes of these virus particles range from simple </span>helical<span> and </span>icosahedral<span> forms for some virus species to more complex structures for others. Most virus species have virions that are too small to be seen with an </span>optical microscope<span>. The average virion is about one one-hundredth the size of the average </span>bacterium<span>.</span>
A) DNA 1 by chromosomal mutation
DNA 2 by genetic mutation
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