Questions

Two series alternate here, with every third number following a different pattern.
In the main series, 4 is added to each number to arrive the next.
In alternate series, 5 is subtracted from each number t arrive the next number.
Here in the main series 
3 + 4 = 7
7 + 4 = 11
11 + 4 = 15
15 + 4 = 19

In alternate series 
24 - 5 = 19
19 - 5 = 14...

The Opium Wars were two wars in the mid-19th century involving Anglo-Chinese disputes over British trade in China and China’s sovereignty. The disputes included the First Opium War (1839–1842) and the Second Opium War (1856–1860).

We know that, preceeded means to come before. 

Hence, the given sentence, preceded in death means that person had died before this person.

For example :: Rahul preceeded Ravi in death, means Rahul died before Ravi.

The pharynx is a passageway shared by both food and air.

Volatile memory is computer memory that requires power to maintain the stored information. It is a temporary memeory which cannot contain information permanently.

Example :: RAM or Random Access Memory