can someone help me with this question please? i get what the question is saying, but i cant seem to work out which one is the right one. The answer is C.
The key sentence is "Neurons will only conduct an impulse if the level of activation is greater than the level of inhibition". The black arrows are inhibitory signals, so we want to choose the situation where the inhibitory signal has the least impact on the signal pathway.
An easy way of working out a solution is assigning a "+1" for secondary activation neurons being activated and "-1" for secondary inhibitory neurons being activated. Let's use this to work out the solution.
Option A: -1, +1, 0 = 0. We can see that the M and N neurons being activated causes the activation of an inhibitory neuron (so -1); O is activated and is an activation neuron, so +1; and because P is inhibitory while Q is activation, there is no activation or inhibition signal transmitted by their receiving activation neuron.
Option B: -1, -1, +1 = -1
Option C: 0, +1, 0 = +1
Option D: +1, -1, 0 = 0
So Option C is the only situation in which an activating signal is passed onto the muscle fibre, causing a contraction (and is therefore the correct answer).
Hope that helps, let me know if it doesn't make sense!