What is the difference between a beta blocker and a calcium-channel blocker?
A) Beta-blockers block norepinephrine and epinephrine from binding to beta-adrenoceptors and a calcium channel blocker inhibits the flow of calcium ions into muscles.
B) Calcium channel blockers block norepinephrine and epinephrine from binding to beta-adrenoceptors and do not relax the heart as beta-blockers do.
C) Although both slow down and relax the heart, only calcium blockers can block norepinephrine and epinephrine from binding to beta-adrenoceptors.
D) Although both slow down and relax the heart, only beta-blockers can inhibit the flow of calcium ions into muscles, thereby inhibiting muscle contraction.
Question 2
Why is the combination of two protons and two neutrons stable, but the combination of two protons and one neutron is not?
A) There are not enough neutrons to overcome the electrical repulsion of the protons.
B) There are not enough neutrons to overcome the nuclear repulsion of the protons.
C) The nuclear attraction between protons is greater than that between neutrons.
D) The electrical repulsion between the two protons is greater in one case than the other.
E) none of the above