Question

BTB (bromothymol blue) is an indicator that changes to yellow in the presence of carbon dioxide (CO 2 ). In neutral solution, BTB is green-blue.



A student was investigating photosynthesis and respiration. She filled four test tubes with water and BTB. She placed water plants in one test tube, water insects in another test tube, and both water insects and plants in another test tube. When she checked the color of the liquid in the test tubes after four hours, she observed the following.

Answer 1

What was most likely present in test tube 2?





A water and BTB only
B water, BTB, and insects
C water, BTB, and plants
D water, BTB, insects, and plants

Answer 2

help pls

Answer 3

WOLFE8

Answer 4

see yellow colour was seen in d presence of CO2
so in test tube 2 there has 2 b an organism which emits co2
now can u guess d ans?