Because it shares two different ideas <span />
Their is your answer the term her would not make any sense in this sentence but their would because asking did either of the sisters bring their umbrella and the term their belongs to both of the sisters
Answer:
There are 2 of what most people call a day which is often called 12 hours which is really just 1 day.
Explanation:
a 24 hour period is known scientifically as a day but can often be misinterpreted as a 12 hour period this happens because of a lack of specificity.
