$(i)$ The ...$a$... help in maintaining the pressure gradient in the sieve tubes.
$(ii)$ Stomata regulate the process of ....$b$..... and gaseous exchange.

  • A
    $a$ - Tracheids,$b$ - Transpiration
  • B
    $a$ - Companion cells,$b$ - Transpiration
  • C
    $a$ - Companion cells,$b$ - $CO_2$ concentration
  • D
    $a$ - Vessels,$b$ - Transpiration

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Similar Questions

Use of anti-transpirant may check

When does the stomatal aperture open?

Assertion : Light is a very important factor in transpiration.
Reason : Light induces stomatal opening and darkness closing of stomata. Therefore,transpiration increases in light and decreases in dark.

The theory of starch-glucose interconversion for stomatal opening and closing was proposed by:

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