Ques: Q: Human blood has a buffering system to minimize extreme changes in what? Read this paragraph and choose the correct option from the provided answers: Buffers work well only for limited amounts of added strong acid or base. Once either solute is all reacted, the solution is no longer a buffer, and rapid changes in pH may occur. We say that a buffer has a certain capacity. Buffers that have more solute dissolved in them to start with have larger capacities, as might be expected. Human blood has a buffering system to minimize extreme changes in pH. One buffer in blood is based on the presence of HCO3 and H2CO3 [H2CO3 is another way to write CO2(aq)]. With this buffer present, even if some stomach acid were to find its way directly into the bloodstream, the change in the pH of blood would be minimal. Inside many of the body's cells, there is a buffering system based on phosphate ions. Choices: - sodium level - calcium - ions - ph A:
Ans: ph

Ques: Q: What is the largest and most complex algae Read this paragraph and choose the correct option from the provided answers: Choices: - open algae - green algae - strange algae - brown algae A:
Ans: brown algae

Ques: Q: Algae are like plants mainly because they contain what? Read this paragraph and choose the correct option from the provided answers: Algae are like plants mainly because they contain chloroplasts. This allows them to make food by photosynthesis. Algae are important producers in water-based ecosystems such as the ocean. On the other hand, algae lack other plant structures. For example, they don't have roots, stems, or leaves. Also unlike plants, some algae can move. They may move with pseudopods or flagella. Choices: - organelles - cells - cell wall - chloroplasts A:
Ans: chloroplasts

Ques: Q: What is the period during which humans become sexually mature called? Read this paragraph and choose the correct option from the provided answers: The reproductive organs grow very slowly during childhood and do not mature until puberty. Puberty is the period during which humans become sexually mature. In the U. S. , boys generally begin puberty at about age 12 and complete it at about age 18. Choices: - adulthood - maturity - adolescence - puberty A:
Ans:
puberty