When you cross the red flower with the blue flower it produced purple offspring

this is incomplete dominance

option a is correct i.e.

explanation:

in context to the membrane of nerve impulse, the outer membrane of neuron is semi permeable that is only sodium ions can pass through the membrane i.e. smaller ions can pass through the membrane while larger ions cannot pass through it.

where is the diagram?

if you insert the diagram ill be able to you