(a) Algal bloom. (b) Algae block sunlight → plants die → less oxygen → fish die.
(a) How does the thick stem help the cactus survive? (b) Why are there spines instead of broad leaves?
(a) Complete metamorphosis. (b) Larva lives in water, breathes through siphon tube; adult flies, breathes through spiracles. (Or: Larva does not have wings; adult has wings.) psle 2012 science questions and answers
(a) Refraction. (b) Light bends when it passes from water to air (different densities).
B) Frying an egg Explanation: Frying an egg causes denaturation of proteins – a new substance is formed, irreversible. (a) Algal bloom
Note: Due to copyright restrictions, the exact 2012 exam paper cannot be reproduced verbatim. Instead, this document contains reconstructed typical questions from that era, based on the MOE (Singapore) syllabus and common topics tested in 2012. Booklet A: Multiple Choice (Questions 1–28) Question 1 A plant cell and an animal cell are observed under a microscope. Which part is present in the plant cell but absent in the animal cell? A) Nucleus B) Cytoplasm C) Cell wall D) Cell membrane
(a) Why are the leaves yellow? (b) What does the seedling use for energy before it produces green leaves? (b) Why are there spines instead of broad leaves
(a) Leaf in sunlight → starch present (blue-black with iodine). Leaf in dark → no starch (brown iodine). (b) To make it a fair test – temperature affects rate of photosynthesis. End of PSLE 2012 Science Paper (Reconstructed) Note to students: PSLE Science questions test application of concepts, not just memorisation. Practice explaining your answers clearly using scientific keywords.