Examkin

Soru

Zorluk: OrtaDetermining Control Groups and Baseline Conditions

Botanists conducted an experiment to evaluate how varying concentrations of ground-level ozone (O3O_3) affect the stomatal conductance of soybean (*Glycine max*) leaves over a 14-day period. Four identical growth chambers were maintained at constant temperature (25∘C25^\circ\text{C}), relative humidity (65%65\%), and photosynthetic photon flux density. The chambers received the following gaseous treatments:

- Chamber 1: Charcoal-filtered air containing 0 ppb0\text{ ppb} of O3O_3.
- Chamber 2: Purified air containing 30 ppb30\text{ ppb} of O3O_3.
- Chamber 3: Purified air containing 60 ppb60\text{ ppb} of O3O_3.
- Chamber 4: Purified air containing 90 ppb90\text{ ppb} of O3O_3.

Which chamber served as the negative control group in this experiment, and what baseline condition did it establish?

  1. Chamber 1; it established baseline stomatal conductance in the complete absence of ozone exposure.Cevap
  2. B
    Chamber 2; it established baseline stomatal conductance under minimal ozone exposure.
  3. C
    Chamber 4; it established the baseline maximum stress response of the soybean plants.
  4. D
    Chambers 2, 3, and 4 combined; they established the average baseline across all ozone concentrations.

Cevap

Chamber 1 served as the control group, establishing baseline stomatal conductance in the absence of ozone exposure.
In experimental design, a negative control group establishes a benchmark standard by eliminating the independent variable. Chamber 1 receives charcoal-filtered air with 0 ppb0\text{ ppb} of O3O_3, allowing researchers to measure normal, unexposed stomatal conductance and confirm that any changes in Chambers 2–4 are caused by ozone exposure.

Adım Adım Çözüm

1
Identify the independent variable tested in the experiment.
The independent variable is the concentration of ground-level ozone (O3O_3) supplied to the chambers.
Determining the manipulated variable allows identification of which group isolates environmental factors from the specific variable being tested.
2
Identify the group that omits the independent variable while maintaining all controlled variables identical.
Chamber 1 receives charcoal-filtered air (0 ppb0\text{ ppb} O3O_3), while temperature, humidity, and light remain identical across all four chambers.
A negative control group must withhold the independent variable so researchers can establish a benchmark measurement.
3
Match the identified control setup with its intended purpose.
Chamber 1 establishes the baseline stomatal conductance of soybean leaves unexposed to ozone stress.
Comparing Chambers 2, 3, and 4 against Chamber 1 isolates changes in stomatal conductance attributable specifically to ozone concentration.

Anahtar Kavram

Determining Control Groups and Baseline Conditions
Bu soruyu puanla

Konular

Determining Control Groups and Baseline Conditions

Bu konudan daha fazla soru