20. According to the pressure-flow hypothesis, phloem transport is driven mainly by: (A) Diffusion along concentration gradients (B) Transpiration pull (C) Turgor pressure dif differences (D) Active transport in sieve elements

9. Which feature best distinguishes bryophytes from vascular plants with respect to life-cycle dominance? (A) Bryophytes possess a dominant sporophyte with vascular tissues (B) Bryophytes rely onon seeds for embryo nourishment (C) Bryophytes have a dominant gametophyte generation that supports a dependent sporophyte (D) Bryophytes exhibit equal dominance of both generations

20. According to the pressure-flow hypothesis, phloem transport is driven mainly by:
(A) Diffusion along concentration gradients
(B) Transpiration pull
(C) Turgor pressure dif differences
(D) Active transport in sieve elements

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