Selected MCQ

Current Question
Which gas exchange occurs in alveoli?
  • A. O₂ out, CO₂ in
  • B. CO₂ out, O₂ in
  • C. Both out
  • D. None
Correct Answer: B
Explanation:
Oxygen diffuses into blood, CO₂ out.
Related Question 1
Which system exchanges gases?
  • A. Digestive
  • B. Respiratory
  • C. Circulatory
  • D. Nervous
Correct Answer: B
Explanation:
Lungs exchange gases.
Related Question 2
Seafloor spreading occurs primarily at:
  • A. Transform boundaries
  • B. Convergent boundaries
  • C. Divergent boundaries
  • D. Hotspot volcanoes only
Correct Answer: C
Explanation:
New oceanic crust forms where plates move apart at mid-ocean ridges.
Related Question 3
In mammals, most nutrient absorption occurs in the:
  • A. Stomach
  • B. Large intestine
  • C. Small intestine
  • D. Esophagus
Correct Answer: C
Explanation:
The small intestine’s villi and microvilli maximize absorptive surface area.
Related Question 4
Which process occurs in the thylakoid membranes of chloroplasts?
  • A. Calvin cycle carbon fixation
  • B. Light-dependent reactions
  • C. Glycolysis
  • D. DNA replication only
Correct Answer: B
Explanation:
Photosystems and electron transport chains of photosynthesis are membrane embedded.
Related Question 5
Independent assortment occurs because homologous chromosome pairs:
  • A. Replicate at different times
  • B. Align randomly at metaphase I
  • C. Separate in mitosis only
  • D. Undergo mutation during cytokinesis
Correct Answer: B
Explanation:
Random orientation of homologs generates different combinations in gametes.