PGR and Intrinsic Plant Growth Control — NEET Biology

Correct answer: D — S1, S2, S3 and S4 only

Let's evaluate each statement based on the NCERT text: S1: "Environmental signals such as light and gravity also affect certain phases/stages of growth." This implies influencing growth directions and patterns. This statement is correct. S2: "Many of the extrinsic factors such as temperature and light, control plant growth and development via PGR." This statement is correct. S3: "Plants follow different pathways in response to environment or phases of life to form different kinds of structures. This ability is called plasticity, e.g., heterophylly in cotton..." This statement is correct. S4: "Some of such events could be: vernalisation, flowering, dormancy, seed germination, plant movements, etc." This statement is correct. S5: "Development is the sum of growth and differentiation... Development in plants (i.e., both growth and differentiation) is under the control of intrinsic and extrinsic factors." The statement says 'primarily controlled by intrinsic genetic factors only', which is incomplete as extrinsic factors also play a role. So, this statement is incorrect. S6: "The final structure at maturity of a cell/tissue is also determined by the location of the cell within." This statement contradicts the idea that it's solely determined by genetic makeup. So, this statement is incorrect. Therefore, statements S1, S2, S3, and S4 are correct. Final Answer: The final answer is D because S1, S2, S3, and S4 are correct.