Nokea
Which of the following vessels carries oxygenated blood?
- A. Pulmonary vein
- B. Superior vena cava
- C. Pulmonary artery
- D. Inferior vena cava
Correct Answer: A
Rationale: The correct answer is A, the pulmonary vein. The pulmonary vein carries oxygenated blood from the lungs back to the heart. It is crucial to differentiate between the pulmonary vein, which carries oxygenated blood, and the pulmonary artery, which carries deoxygenated blood. This understanding is fundamental in comprehending the flow of oxygen-rich and oxygen-poor blood within the cardiovascular system.
You may also like to solve these questions
In order to determine the effects of energy drinks on women's running speed, researchers gave 300 women an energy drink and then recorded the time it took each of them to run 2 miles. After collecting the results, researchers concluded that energy drinks increase the speed of running in women. Which of the following further tests would best help to support this conclusion? Repeat the same experiment, using 300 men.
- A. Repeat the experiment, giving half of the men water and the other half the energy drink.
- B. Repeat the experiment having half of the men run 2 miles and the other half run 5 miles.
- C. Repeat the experiment, giving the men two different energy drinks.
- D. Repeat the experiment, giving the men two different energy drinks.
Correct Answer: B
Rationale: To further support the conclusion that energy drinks increase running speed in women, the best approach would be to repeat the experiment with men. By having half of the men run 2 miles (similar to the original experiment with women) and the other half run a longer distance such as 5 miles, researchers can determine if the effects of energy drinks on running speed are consistent across different distances. This design allows for a comparative analysis between genders and varying running distances, providing a more comprehensive understanding of the impact of energy drinks on running performance.
Which of the following blood vessels is affected by a myocardial infarction?
- A. coronary
- B. vena cava
- C. pulmonary
- D. aorta
Correct Answer: A
Rationale: A myocardial infarction affects the coronary arteries, not the vena cava, pulmonary, or aorta. The coronary arteries supply blood to the heart muscle, and blockages in these arteries can result in a heart attack. The vena cava is a large vein that carries deoxygenated blood back to the heart, the pulmonary arteries carry deoxygenated blood from the heart to the lungs for oxygenation, and the aorta is the main artery that carries oxygenated blood from the heart to the rest of the body. These vessels are not typically associated with myocardial infarctions as they perform different functions within the circulatory system.
Why does dipping an apple slice in lemon juice prevent it from browning through an enzymatic reaction?
- A. Lemon juice has a pH that inactivates the enzymes.
- B. Lemon juice has enzymes that reverse the browning.
- C. Lemon juice functions to dilute the brown material.
- D. Lemon juice functions to bleach the brown material.
Correct Answer: A
Rationale: The correct answer is A: Lemon juice has a pH that inactivates the enzymes. Enzymatic browning in apples is caused by the enzyme polyphenol oxidase. When an apple is sliced, the enzyme comes into contact with oxygen in the air, leading to the browning process. Lemon juice contains citric acid, which lowers the pH of the apple's surface, creating an acidic environment that inactivates the polyphenol oxidase enzyme, thus preventing the browning reaction. This acidic environment denatures the enzyme, rendering it unable to catalyze the browning reaction. Therefore, by dipping the apple slice in lemon juice, the enzymatic activity that causes browning is effectively inhibited, maintaining the apple's color and freshness.
What is the atomic number of an atom that has 12 protons and 12 neutrons?
- A. 1
- B. 144
- C. 12
- D. 24
Correct Answer: C
Rationale: The atomic number of an element is determined by the number of protons in its nucleus. In this case, the atom has 12 protons, which directly corresponds to its atomic number. Neutrons have no impact on the atomic number; they contribute to the atomic mass. The atomic number uniquely identifies an element based on the number of protons in its nucleus. Therefore, the correct answer is 12, as it represents the number of protons in the nucleus and defines the element, regardless of the presence of neutrons.
A researcher writes a grant proposal to repeat an experiment that was recently published by another researcher. Which of the following statements best supports the grant proposal?
- A. Funding this grant proposal will allow for the continuation of studying this topic.
- B. Repeating the published work will provide independent confirmation of the results.
- C. Repeating published work with altered variables will extend the previous findings.
- D. Supporting this important research will be beneficial for science in the long term.
Correct Answer: B
Rationale: The best support for the grant proposal is that repeating the published work will provide independent confirmation of the results. This is crucial for scientific research as it strengthens the validity and reliability of the original findings. Independent confirmation is essential for verifying the reproducibility and credibility of the study. Options A, C, and D, though somewhat relevant, do not directly address the primary purpose of repeating the experiment for validation and verification in scientific research.