Which new phenomenon did griffith focus on during his work with pneumonia-causing bacteria and mice?

when Griffith was experimenting with pneumonia-causing bacteria he discovered that when two cultures were mixed, somehow the harmless bacteria changed, and that organism contained information that could be passed on to another organism.

and the phenomenon is stated right there in the answer

~batmans wife dun dun dun...

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.