A ray of light goes from one transparent material into another is called

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Explanation:

When a light ray passes from air into water a similar thing occurs: the light ray is bent as it strikes the surface of the water. This 'bending of a ray of light' when it passes from one substance into another substance is called refraction

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.

the median of the data is 4.5.