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

the element that provides strength to the exoskeletons of clams and oysters is phosphorus.

this is so because calcium carbonate is the main component in the shells. calcium carbonate is strengthened by phosphorus.

explanation:

"a.) well–developed vascular system."