CBSE Class 11-science Answered

Let us consider neuron H.

• When an input signal of 2 units or greater than 2 units was supplied, an action potential was recorded in H. From the graph, it can be seen that neuron H did not generate an action potential when the input signal was less than 2 units and hence, no action potential was recorded at time frames of 1, 3, 4, 5, 7, 8, 9, 11, 12 and 13 seconds.

Let us consider neuron S.

• Even in this case, when an input signal of 2 units or greater than 2 units was supplied, an action potential was recorded in S. However, from the graph, it can be seen that neuron S did generate an action potential of lesser amplitude even when the input signal was less than 2 units. As a result, smaller action potential was recorded even at time frames of 3, 4, 5, 7, 8, 11, 12 and 13 seconds.

Thus, we can conclude that both neuron H and S initiate an action potential when the input signal is greater than or equal to 2 units, but only neuron S can sustain it for more than 1 second.

The correct answer to the question are options B and C.