Answer:
Firstly, the partial pressure of nitrogen (78%) is crucial to breathing purposes. Without this pressure, the lungs will burst and animals cannot survive.
Secondly, nitrogen is required for the formation of amino acids (building blocks of proteins) and other organic compounds that are necessary for the survival of living organisms. Principally, in the atmosphere, nitrogen is present in the form of molecular nitrogen (N2). N2 is fixed by nitrogen-fixing bacteria that form nitrates and nitrites. These molecules are then used in biochemical processes to produce proteins (amino acids) and other organic compounds. In the absence of nitrogen, these processes could become seize of limited significantly thus affecting life overall.
Thirdly, nitrogen and its derivatives act as greenhouse gases that maintain the Earth's temperature within a range that supports life. Yes, the increased abundance of nitrous oxides is not good because of acid rain and other issues, however, still, the presence of nitrogen is important for life on this planet.
A vaccine uses a live pathogen that is too weak to make you sick. Once it enters your body you defeat it easily. Now that yur body is familiar with it your body can fight off the disease in the future.
Mendeleev called the rows periods.
That is binary fission, 'cause in this process, chromosome number doubles to it's original value whereas in meiosis it gets halved.
In short, Your Answer would be Option D
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The correct answer is: B) -20 kcal/mol
Enzymes are catalysts of chemical reactions, they speed up the reaction by lowering the activation energy, but don't affect the ∆G (change of Gibbs free energy). The changes in free energy occurs due to change in concentrations of reactants and products and don't have anything to do with the presence or absence of an enzyme.