Although the bite of
brown recluse spiders are rarely fatal, they cause chronic flesh wounds, posing the greatest danger to the infant and elderly, who are particularly vulnerable to its poison.
(A) brown recluse spiders are rarely fatal, they cause chronic flesh wounds, posing the greatest danger to the infant and elderly, who are particularly vulnerable to its
(B) brown recluse spiders are rarely fatal, they cause chronic flesh wounds and pose the greatest danger to the infant and elderly, who are particularly vulnerable to their
(C) the brown recluse spider is rarely fatal, it causes chronic flesh wounds, posing the greatest danger to the infant and elderly, who are particularly vulnerable to their
(D) the brown recluse spider is rarely fatal, it causes chronic flesh wounds and poses the greatest danger to infants and the elderly, who are particularly vulnerable to its
(E) the brown recluse spider is rarely fatal, they cause chronic flesh wounds, posing the greatest danger to the infant and elderly, who are particularly vulnerable to its
The bite is the subject of first part of sentence, so...
1>
is should be verb to agree with singular subject
the bite 2> next sentence should start with singular pronoun
it.
Now, Options A, B and E are eliminated.
C is incorrect because '
their' is plural pronoun, whereas sentence talks about singular spider.
Hence Option D is correct choice.
About your doubt:
--> In the second sentence, pronoun should talk about the subject in first sentence. See difference between two lines.
the bite of the brown recluse spider is rarely fatal,
it causes ... The brown recluse spiders bite anywhere on the skin,
they cause ...