What are stomata? a) Structures for photosynthesis
b) Small openings on leaf surfaces
c) Roots of plants
d) Water-absorbing cells
Answer: b) Small openings on leaf surfaces
Which gas primarily enters the leaf through the stomata? a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Methane
Answer: b) Carbon dioxide
What is the primary function of stomata? a) Absorbing nutrients
b) Water storage
c) Gas exchange
d) Photosynthesis
Answer: c) Gas exchange
Stomata are surrounded by which type of cells? a) Parenchyma cells
b) Guard cells
c) Sclerenchyma cells
d) Xylem cells
Answer: b) Guard cells
What happens to stomata during hot and dry conditions? a) They remain open
b) They close
c) They double in number
d) They become larger
Answer: b) They close
Which hormone is primarily responsible for stomatal closure in response to drought? a) Auxin
b) Ethylene
c) Abscisic acid
d) Gibberellin
Answer: c) Abscisic acid
During photosynthesis, what gas is released through the stomata? a) Nitrogen
b) Carbon dioxide
c) Oxygen
d) Hydrogen
Answer: c) Oxygen
How do stomata contribute to transpiration? a) By absorbing water
b) By releasing oxygen
c) By allowing water vapor to escape
d) By closing during the night
Answer: c) By allowing water vapor to escape
What is the primary factor influencing the opening and closing of stomata? a) Soil moisture
b) Light intensity
c) Temperature
d) Humidity
Answer: b) Light intensity
In which part of the plant are stomata most commonly found? a) Roots
b) Stems
c) Leaves
d) Flowers
Answer: c) Leaves
Which type of plant typically has more stomata on its leaves? a) Xerophytes
b) Hydrophytes
c) Mesophytes
d) Halophytes
Answer: c) Mesophytes
What is the role of guard cells in stomatal function? a) To absorb nutrients
b) To photosynthesize
c) To regulate the size of the stomatal opening
d) To store water
Answer: c) To regulate the size of the stomatal opening
How do increased carbon dioxide levels in the atmosphere affect stomatal behavior? a) They cause stomata to close
b) They have no effect
c) They cause stomata to open
d) They increase the number of stomata
Answer: c) They cause stomata to open
What type of photosynthesis is associated with plants that have fewer stomata? a) C3 photosynthesis
b) C4 photosynthesis
c) CAM photosynthesis
d) Dark reactions
Answer: c) CAM photosynthesis
Which of the following is NOT a factor affecting stomatal opening? a) Light
b) Water availability
c) Soil pH
d) Carbon dioxide concentration
Answer: c) Soil pH
What is the primary mechanism by which guard cells change their shape? a) Water uptake
b) Hormonal control
c) Temperature changes
d) Nutrient absorption
Answer: a) Water uptake
Which of the following conditions would most likely result in the stomata being closed? a) High humidity
b) High light intensity
c) Low soil moisture
d) Cool temperatures
Answer: c) Low soil moisture
Stomatal density can vary based on which environmental factor? a) Soil type
b) Wind speed
c) Atmospheric CO2 levels
d) All of the above
Answer: d) All of the above
What type of plant adaptations may involve changes in stomatal function? a) Photosynthetic adaptations
b) Water-use efficiency adaptations
c) Nutrient absorption adaptations
d) All of the above
Answer: b) Water-use efficiency adaptations
Which of the following best describes the relationship between stomatal opening and photosynthesis? a) Directly proportional
b) Inversely proportional
c) No relationship
d) Variable relationship
Answer: a) Directly proportional
How does humidity influence stomatal behavior? a) High humidity opens stomata
b) Low humidity opens stomata
c) Humidity has no effect
d) Humidity always closes stomata
Answer: a) High humidity opens stomata
Which of the following processes primarily occurs at night regarding stomata? a) Stomata open for photosynthesis
b) Stomata close to conserve water
c) Stomata double in number
d) Stomata are inactive
Answer: b) Stomata close to conserve water
In plants that perform CAM photosynthesis, when do stomata typically open? a) During the day
b) During the night
c) At dawn
d) At noon
Answer: b) During the night
What effect does temperature have on stomatal opening? a) Higher temperatures always close stomata
b) Higher temperatures can cause stomata to open
c) Temperature has no effect on stomata
d) Lower temperatures always open stomata
Answer: b) Higher temperatures can cause stomata to open
Which part of the plant is least likely to contain stomata? a) Leaves
b) Flowers
c) Roots
d) Stems
Answer: c) Roots
What environmental stress can lead to increased stomatal density over generations? a) Excess water
b) High light
c) Drought
d) Low temperature
Answer: c) Drought
The process of transpiration primarily involves which gas? a) Oxygen
b) Carbon dioxide
c) Water vapor
d) Nitrogen
Answer: c) Water vapor
What physiological process directly affects the turgor pressure in guard cells? a) Photosynthesis
b) Respiration
c) Water uptake
d) Nutrient absorption
Answer: c) Water uptake
In which plant group are stomata typically found in the highest densities? a) Gymnosperms
b) Angiosperms
c) Ferns
d) Bryophytes
Answer: b) Angiosperms
Which mechanism primarily drives the diffusion of gases through stomata? a) Active transport
b) Osmosis
c) Concentration gradient
d) Capillary action
Answer: c) Concentration gradient