Read the following description of Tube #4:

Question

Tube #4 contains:

Bromothymol blue (BTB)
Carbon dioxide
Not exposed to light
No Elodea present
Initially yellow-green in color
After 24 hours, Tube #4 is still yellow-green in color. Which of the answer choices below describes why?

(1 point)
Responses

Tube #4 is still yellow-green in color because the carbon dioxide was absorbed.
Tube #4 is still yellow-green in color because the carbon dioxide was absorbed.

Tube #4 is still yellow-green in color because carbon dioxide was released.
Tube #4 is still yellow-green in color because carbon dioxide was released.

Tube #4 is still yellow-green in color because it was unable to perform photosynthesis.
Tube #4 is still yellow-green in color because it was unable to perform photosynthesis.

Tube #4 is still yellow-green in color because it performed photosynthesis.

Answer 1

The correct response is:

Tube #4 is still yellow-green in color because it was unable to perform photosynthesis.

Explanation: Tube #4 does not contain Elodea (a type of aquatic plant) and is not exposed to light, both of which are necessary conditions for photosynthesis to occur. Without photosynthesis, carbon dioxide cannot be utilized by the plant, leading to the retention of a yellow-green color in the bromothymol blue (BTB) solution, which indicates a neutral to weakly acidic environment typical for the lack of carbon uptake.