Reflex action immediately involves

Which of the following is an example of a reflex action?

The watering of the mouth at the sight of delicious food is a result of:

Given below are different components of a reflex arc:
$I$. Effector organ
$II$. Interneuron
$III$. Motor neuron
$IV$. Sensory neuron
$V$. Sensory receptor
Arrange these in the correct order of the action potential that follows a sensory receptor stimulation.

What is reflex action?

If the light source in front of an eye becomes bright suddenly,what happens?