Changes in the physical environment, whether (1) occurring or ( induced, have thus contributed to the expansion of some (3) the (4) of new distinct species as populations diverge under different conditions, and the decline–and sometimes the (5) –of some species.

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.

bc blah

explanation:

bc blah