Hemoglobin consists of two alpha globin polypeptides and two beta globin polypeptides. Which level of protein structure is present in hemoglobin but is absent in the alpha and beta polypeptides that make up hemoglobin?

The breakdown of food is accomplished by enzymes. a. physical b. chemical c. mechanical d. none of the above

Which statement best describes how the loudness of the sound affects the high-pressure region created by the sound wave? a. a louder sound has no effect on the pressure created. b. a louder sound means a high-pressure region that is higher. c. a louder sound means a high-pressure region that is not as high.

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