Why is mutualism more common in tropical ecosystems then in other ecosystems?

Which of these is the most likely consequence of falling petroleum price

What material did the moon come from?

Astudent poured a solution of bromothymol blue indicator into three test tubes. then he placed an aquatic plant in two of the test tubes, as shown below. he placed a stopper on each test tube and placed them all in the dark for 24 hours. bromothymol blue turns from blue to yellow in the presence of co2