I need help please in ASAP

Which is the graph of the piecewise function f(x)? f(x) = image for option 1 image for option 2 image for option 3 image for option 4

What type of plant is good for a bioassay and where can i buy it? i only have a month.

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