21. Which vitamin can be synthesized in skin with adequate sunlight exposure?
✅ B. Vitamin D
Sunlight exposure enables vitamin D synthesis in skin. Read more
Author: Sheeraz Ahmed – Page 2
22. Which part of a plant performs most photosynthesis?
✅ A. Leaves
Most photosynthesis occurs in leaves. Read more
23. At standard atmospheric pressure, water boils at?
✅ A. 100°C
Water boils at 100°C under standard atmospheric pressure. Read more
24. Which blood cells primarily carry oxygen?
✅ C. Red blood cells
Red blood cells carry oxygen using hemoglobin. Read more
25. At standard atmospheric pressure, water freezes at?
✅ A. 0°C
Water freezes at 0°C under standard atmospheric pressure. Read more
26. What is the basic structural and functional unit of life?
✅ B. Cell
The cell is the basic structural and functional unit of life. Read more
27. Which planet is closest to the Sun?
✅ B. Mercury
Mercury is the closest planet to the Sun. Read more
28. What force attracts objects toward Earth?
✅ D. Gravity
Gravity attracts masses toward one another. Read more
29. Which organ pumps blood through the human body?
✅ D. Heart
The heart pumps blood through the circulatory system. Read more
30. Which gas is most abundant in Earth’s atmosphere?
✅ B. Nitrogen
Nitrogen makes up about 78% of Earth's atmosphere. Read more