Question

what does an abrupt change from blue to yellowish - green in bromothymol blue suggest about co₂ levels? decreased co₂ level increased co₂ levels decreased o₂ levels no change in co₂ levels

Explanation:

Bromothymol blue is a pH - indicator. Carbon dioxide dissolves in water to form carbonic acid, which lowers the pH. A change from blue to yellowish - green indicates a more acidic environment, suggesting increased CO₂ levels as more CO₂ leads to more carbonic acid formation.

Answer:

increased CO₂ levels