The main purpose of this article is a
to persuade people to play it safe and stay inside during cold weather
b
to explain two dangers of cold temperatures and how to guard against them
c
to celebrate the bravery and accomplishments of Sir Ranulph Fiennes
d
to inform the reader about terms commonly used in winter weather reports

B

Explanation:

b

to explain two dangers of cold temperatures and how to guard against them

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.

prokaryotic cells do not have a nucleus in which the dna is stored in, it floats freely inside the cell.

eukaryote cells do have a nucleus in which the dna is stored in.