The opening and closing of stomata is directly controlled by the___________?
Correct answer: C. Light
- A. Temperature
- B. pH
- C. Light
- D. None of these
Explanation
Light directly stimulates guard cells to accumulate solutes, causing water to enter and increasing their turgor, which opens the stomatal pore. Temperature and pH can influence stomatal behaviour, but light is the principal direct environmental stimulus in this context. Students may choose temperature because it affects transpiration, but transpiration itself does not directly open the stomata.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About Biological Importance of Water
Water supports life through its polarity, hydrogen bonding and ability to dissolve ionic and polar substances. Its high specific heat, heat of vaporization, cohesion, adhesion and incompressibility help regulate temperature, transport materials and maintain structure, while hydrolysis and osmosis depend directly on water.
Practise Biological Molecules
1,790 free Biological Molecules MCQs from Biology, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Biology questions like this
Biology is on 8 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Biological Importance of Water questions
There are _________ hypothesis which may explain opening and closing of stomata?
Low level of CO2 favours _________ of the stomata.
Symbionts which help plants in uptake of phosphorous and trace metals such as zinc and copper.
___________ function as multisensory hydraulic valve?
Stomatal transpiration is __________ of total transpiration
A pressure created by active secretion of salts and other solutes from other cells into xylem sap is called___________?