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🔬 Biology  ·  Plant Growth and Development  ·  NEET

The coleoptile bending experiments that first hinted at auxin were carried out by:

Answer: The two Darwins.

  • A Gregor Mendel
  • B Robert Hooke
  • C The two Darwins
  • D Melvin Calvin

Correct answer: C. The two Darwins

Explanation: Charles Darwin and his son Francis showed that grass coleoptiles bend towards light because the tip senses it - the first clue to auxin.

Geometric Growth: the Sigmoid Curvetimegrowthlag phaselog/exponential phasestationary phaseGrowth starts slow, accelerates rapidly, then plateaus as resources become limiting

Geometric growth (where both daughter cells keep dividing) produces this classic S-shaped curve: a slow lag phase, a rapid exponential phase, and a levelling-off stationary phase as nutrients or space become limiting - the same fundamental pattern seen in population growth.

Concept context

Phases of plant growth, the five classical plant hormones plus newer ones, photoperiodism, vernalization, and seed dormancy.

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