The scientist who proposed the theory of evolution by natural selection is: MCQ with Answer and Explanation

Explanation:
During the light reactions of photosynthesis, photolysis of water occurs at photosystem II, splitting water into protons, electrons, and molecular oxygen. The oxygen comes from water, not CO₂. This was demonstrated by using isotopically labeled oxygen (H₂O¹⁸). Glucose is formed in the Calvin cycle. Chlorophyll absorbs light but does not provide oxygen. The overall equation: 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O.

Explanation:
Self-pollination (autogamy) occurs within the same flower or between flowers of the same plant. Cross-pollination (allogamy) involves different plants. Hydrophily is pollination by water, anemophily by wind. Self-pollination ensures genetic uniformity, while cross-pollination promotes variation. Cleistogamous flowers (e.g., groundnut) are obligate self-pollinators.

Explanation:
Carrot and radish are examples of modified taproots where the primary root swells to store food. Prop roots are adventitious (banyan), fibrous roots are fine and branching (grasses), adventitious arise from stems/leaves.