A ball is thrown upward with initial velocity 20 m/s. Taking g = 10 m/s², what is the maximum height reached?

The correct answer is C: 20 m. Using v² = u² - 2gh, where final velocity v = 0 at maximum height: 0 = (20)² - 2(10)h, so h = 400/20 = 20 m.

The calcium pump in plant cell vacuole membrane is primarily involved in:

The correct answer is C: Sequestering calcium ions for cellular signaling. Calcium pumps actively transport Ca²⁺ into vacuoles, serving as a calcium reservoir for second messenger signaling in plant cells.

Which statement about alpha decay is correct?

The correct answer is A: An alpha particle is a helium nucleus with 2 protons and 2 neutrons. An alpha particle is a helium-4 nucleus (₂He⁴) with 2 protons and 2 neutrons. Alpha decay decreases atomic number by 2 and mass number by 4. Alpha particles have low penetration power.

Which phenomenon occurs when sound waves bend around obstacles?

The correct answer is C: Diffraction. Diffraction is the bending of waves around obstacles or through openings. This explains why we can hear sounds around corners.

Which of the following statements about plasmolysis is TRUE?

The correct answer is D: Both A and B. Plasmolysis is the shrinkage of protoplasm away from the cell wall when placed in hypertonic solution. It's reversible if not prolonged.