Answer:
Burning of a candle
Explanation:
All of the other things cannot be undone. the burning of a candle can. Blow the candle out and you have undone a phisical change
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For example, pH can have an effect of the state of ionization of acidic or basic amino acids. Acidic amino acids have carboxyl functional groups in their side chains. Basic amino acids have amine functional groups in their side chains. If the state of ionization of amino acids in a protein is altered then the ionic bonds that help to determine the 3-D shape of the protein can be altered. This can lead to altered protein recognition or an enzyme might become inactive.
Changes in pH may not only affect the shape of an enzyme but it may also change the shape or charge properties of the substrate so that either the substrate connot bind to the active site or it cannot undergo catalysis.
In geneal enzyme have a pH optimum. However the optimum is not the same for each enzyme.
Answer:
Pneumococcal polysaccharide vaccine
Explanation:
This is a liquid vaccine, and these types of vaccines should not be frozen, because if they do they lose their potency and no longer protect the individual from infections. In fact when these types off vaccines are frozen they can cause local reactions such as sterile abscesses.
Answer: The ice caps are melting
Explanation: Because of global warming caused by the burning of fossil fuels and other factors the ice caps are melting and so the sea level is rising
