The correct answer is option (B) lemon juice.
pH refers to the logarithmic scale used to indicate the acidity or basicity of an aqueous solution. It is the negative of the base 10 logarithm of the activity of the hydrogen ion. Solutions with a pH less that 7 are considered acidic and the solutions with a pH greater that 7 are considered to be basic. A pH of 7 is neither an acid nor a base and is considered neutral.
An acid has a high concentration of hydrogen ions (H+) and a base has a low concentration of hydrogen ions. Higher the hydrogen ion concentration, pH is acidic. Among the given substances, lemon juice has a pH of 2, urine has a pH of 6, tomato juice has a pH of 4 and black coffee has a pH of 5. Since lemon juice has a pH of 2, it has the lowest –OH ion concentration.
Answer: Bacterial cells can be genetically modified so that they have the gene for producing human insulin. As these modified bacteria grow, they produce human insulin.
Explanation:
Plants use energy from sunlight to turn water and carbon dioxide from what they get into an energy-rich sugar called glucose. This process is called photosynthesis, which means “making things with light”. In photosynthesis, the energy in light is absorbed by photopigments.
Answer: C. Oil from the oil spill could enter aquatic organisms, like fish, which could make people sick.
Explanation:
Oil spill in water body can be caused by the industrial oil discharge, emission of vehicle oil in water body.
The oil may contain toxic chemicals which could be consumed by the fishes or other aquatic organisms. The fishes and other edible aquatic organisms if consumed by human beings can make people unhealthy or sick.
Photosynthesis allows plants, algae and certain bacteria to turn sunlight into chemical energy. The amazing feat is achieved because sunlight can fuel a reaction between water and carbon dioxide that, in turn, produces carbohydrates (simple sugars) and oxygen.
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