question_answer

The diagram shows the sequence of events occurring as an action potential arrives at a synapse. The numbered arrows represent the movement of substances across the membranes. What are the substances moving across the membranes?

1        2        3        4        5

A)

\[{{K}^{+}}\]   \[N{{a}^{+}}\]   \[Ach.\,\]  \[C{{a}^{+}}\]   \[{{K}^{+}}\]

B)

\[{{K}^{+}}\]   \[N{{a}^{+}}\]   \[{{K}^{+}}\]     \[C{{a}^{+}}\]   \[Ach.\,\]

C)

\[N{{a}^{+}}\]  \[{{K}^{+}}\]    \[C{{a}^{+}}\]   \[Ach.\,\]  \[N{{a}^{+}}\]

D)

\[N{{a}^{+}}\]  \[{{K}^{+}}\]    \[N{{a}^{+}}\]  \[Ach.\,\]   \[C{{a}^{+}}\]