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

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

Answer 1

The correct response is:

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

This is because Tube #4 does not contain Elodea (a type of aquatic plant), which means there are no photosynthetic organisms present to convert carbon dioxide into oxygen and other byproducts through photosynthesis. Since no photosynthesis occurs, the color of the bromothymol blue remains unchanged (yellow-green) as there is no increase in pH (which would occur if carbon dioxide was utilized).