Nokea
What is the primary mode of CO2 transport in the body?
- A. Bicarbonate
- B. Carbamino compounds
- C. None of these
- D. Plasma
Correct Answer: A
Rationale: The correct answer is A: Bicarbonate. In the body, the primary mode of CO2 transport is as bicarbonate. Carbon dioxide is converted to bicarbonate in red blood cells as part of the bicarbonate buffer system, which helps maintain the pH balance in the blood. Bicarbonate is then transported in the plasma to the lungs where it is converted back to carbon dioxide for exhalation. While carbamino compounds also play a role in CO2 transport by binding to amino groups on proteins, bicarbonate is the main mode of transport for carbon dioxide in the body. Options B, C, and D are incorrect as they do not represent the primary mechanism of CO2 transport in the body.
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Which of the following structures helps filter pathogens from the blood?
- A. Lymph nodes
- B. Kidneys
- C. Spleen
- D. Pancreas
Correct Answer: C
Rationale: The spleen is the correct answer. The spleen is a vital organ in the immune system responsible for filtering pathogens from the blood. It contains specialized immune cells that aid in recognizing and eliminating harmful substances. Additionally, the spleen plays a role in recycling old red blood cells. Choices A, B, and D are incorrect. Lymph nodes primarily filter lymph fluid, not blood. Kidneys are involved in filtering waste and regulating fluid balance, not specifically filtering pathogens from the blood. The pancreas functions in hormone regulation and digestion, unrelated to filtering pathogens from the blood.
What is the independent variable in this experiment?
- A. Time
- B. Dog weight
- C. Dog species
- D. Dog food type
Correct Answer: D
Rationale: The independent variable is the factor that is manipulated by the researcher to observe its effects on the dependent variable. In this experiment, the researcher is likely changing the type of dog food, and this manipulation is what impacts the outcome being measured. Therefore, 'Dog food type' is the independent variable. Choices A, B, and C do not represent the variable being intentionally changed by the researcher, making them dependent variables or other factors not directly controlled or manipulated in this experiment.
Water is considered a universal solvent due to its ____.
- A. Cohesion
- B. Adhesion
- C. Molarity
- D. Dilution
Correct Answer: B
Rationale: The correct answer is B: Adhesion. Water's polarity allows it to dissolve many substances due to its ability to adhere to and interact with other molecules, making it an effective solvent. Cohesion refers to water molecules sticking together, molarity is a measure of concentration, and dilution refers to the process of reducing the concentration of a solute in a solution, none of which directly relate to water's role as a universal solvent.
Which part of the digestive system is primarily responsible for absorbing nutrients?
- A. Stomach
- B. Small intestine
- C. Esophagus
- D. Large intestine
Correct Answer: B
Rationale: The small intestine is the primary site for nutrient absorption in the digestive system. It is lined with specialized cells that facilitate the absorption of nutrients such as carbohydrates, proteins, fats, vitamins, and minerals into the bloodstream for distribution throughout the body. While the stomach plays a role in digestion by breaking down food with acid and enzymes, the actual absorption of nutrients occurs mainly in the small intestine. The esophagus is responsible for transporting food from the mouth to the stomach, but it does not absorb nutrients. The large intestine primarily absorbs water and electrolytes, not nutrients.
Which type of blood vessel carries blood back to the heart?
- A. Artery
- B. Vein
- C. Capillary
- D. Lymphatic vessel
Correct Answer: B
Rationale: The correct answer is B: Vein. Veins carry blood back to the heart from various parts of the body, functioning as the vessels that return blood to the heart. Arteries, on the other hand, carry blood away from the heart to different parts of the body to deliver oxygen and nutrients. Capillaries are tiny blood vessels where the exchange of gases, nutrients, and waste products occurs between the blood and tissues. Lymphatic vessels are part of the lymphatic system, responsible for maintaining fluid balance and aiding in immunity. Therefore, the correct choice is B as it directly relates to the blood flow back to the heart.