Select all of the following statements that correctly compare the t and r forms of allosteric enzyme subunits.
a. the t form has a different shape than the r form.
b. both the t form and r form can exist without substrate bound to the active site.
c. a t form and r form cannot exist at the same time in an allosteric enzyme.

Select the correct answer. which mutation is harmful to the organism? a. a mutation allowing moths to camouflage better on blackened tree bark b. a mutation making staphylococcus aureus resistant to the antibiotic methicillin c. a mutation inhibiting human immunodeficiency virus from attaching to and entering the cell d. a mutation causing uncontrolled cell division e. a mutation giving plant leaves a bitter taste to discourage herbivores from eating them