Where is oxygen exchanged between blood and tissues?
- A. capillaries
- B. veins
- C. ventricles
- D. arteries
Correct Answer: A
Rationale: Oxygen is exchanged between blood and tissues primarily at the capillaries. Capillaries are the smallest blood vessels where the exchange of oxygen, nutrients, and waste products occurs between the blood and the tissues. This exchange process is crucial for delivering oxygen to the body's cells and eliminating carbon dioxide waste. Veins carry blood back to the heart, arteries carry blood away from the heart, and ventricles are the lower chambers of the heart responsible for pumping blood. Therefore, capillaries are the correct answer for where oxygen is exchanged between blood and tissues.
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Which of the following is the cartilaginous flap that protects the larynx from water or food while still allowing the flow of air?
- A. epiglottis
- B. bronchioles
- C. epithelium
- D. tongue
Correct Answer: A
Rationale: The epiglottis is the cartilaginous flap that protects the larynx from water or food while still allowing the flow of air. When we swallow, the epiglottis covers the entrance to the larynx, preventing food or liquid from entering the airway and instead directing them towards the esophagus for digestion. Choice B, bronchioles, are small airway branches within the lungs and are not involved in protecting the larynx from food or water. Choice C, epithelium, refers to the tissue that lines the surfaces of organs and structures in the body, but it is not the specific structure that protects the larynx as described. Choice D, tongue, plays a role in taste, speech, and swallowing, but it is not the cartilaginous flap that protects the larynx.
Which of the following basic mechanisms of evolution is described as the process where organisms with an advantageous trait survive more often and produce more offspring than organisms without the advantageous trait?
- A. gene flow
- B. genetic drift
- C. mutation
- D. natural selection
Correct Answer: D
Rationale: Natural selection is the basic mechanism of evolution that explains how organisms with advantageous traits are more likely to survive and reproduce in a given environment. This leads to the passing on of these favorable traits to their offspring, causing these traits to become more common in the population over time, resulting in evolutionary change. Natural selection is driven by environmental pressures that support the survival and reproduction of individuals with specific traits. Gene flow refers to the movement of genes between populations, genetic drift is the change in allele frequencies due to random events, and mutation is the source of genetic variation but is not the process by which advantageous traits become more prevalent in a population.
Which of the following is NOT a function of the liver?
- A. nutrient processing
- B. blood filtration and detoxification
- C. cholesterol and lipoprotein production
- D. insulin production and blood sugar regulation
Correct Answer: D
Rationale: The correct answer is D. The liver does not produce insulin; instead, insulin is produced by the pancreas. The liver plays a crucial role in regulating blood sugar levels by storing and releasing glucose but does not directly produce insulin. Choices A, B, and C are functions of the liver. Nutrient processing, blood filtration, detoxification, cholesterol, and lipoprotein production are essential roles performed by the liver to maintain overall metabolic balance and health.
Which of the following describes how atomic radius varies across the periodic table?
- A. Atomic radius increases from top to bottom and left to right on the periodic table.
- B. Atomic radius increases from top to bottom and right to left on the periodic table.
- C. Atomic radius increases from top to bottom and toward the halogens on the periodic table.
- D. Atomic radius increases from top to bottom and toward the noble gases on the periodic table.
Correct Answer: A
Rationale: Atomic radius tends to increase from top to bottom and left to right on the periodic table. This is because as you move down a group (top to bottom), new energy levels are added, increasing the distance of the outer electrons from the nucleus and thus increasing the size of the atom. On the other hand, as you move from left to right across a period, the number of protons and electrons increases, leading to a stronger nuclear charge that attracts the electrons closer to the nucleus, resulting in smaller atomic radii. Choice B is incorrect as atomic radius does not increase from right to left. Choices C and D are incorrect as they incorrectly associate the trend with specific groups of elements (halogens and noble gases) rather than the general trend observed on the periodic table.
Which of the following describes the muscular organ that processes food material into increasingly smaller pieces, mixes it with saliva to create a bolus, and creates a barrier to transport food into the esophagus?
- A. pharynx
- B. tongue
- C. diaphragm
- D. stomach
Correct Answer: B
Rationale: The tongue is the muscular organ responsible for manipulating food material in the mouth, breaking it down into smaller pieces, and mixing it with saliva to form a bolus. It also plays a crucial role in pushing the food bolus towards the back of the mouth to facilitate swallowing and transport the food into the esophagus. The pharynx is involved in swallowing and directing food to the esophagus after it passes the mouth. The diaphragm is a muscle involved in the breathing process, not food processing. The stomach is an organ responsible for further digestion of food after it passes through the esophagus.