Questions

Henry's Law tells that the solubility of a gas is directly proportional to the partial pressure of the gas above the solvent. Hence under high pressure, more gas is dissolved.

Also that Henry's Law involves a constant which is temperature-dependent. Under high temperatures, less gas is dissolved whereas under low temperatures, more gas is dissolved.

For Example ::  

You can think of a can of soda. The contents are under pressure and if you shake the can before opening, the soda fizzes out all over as you open it. So the higher the pressure, the more gas or more CO2 can be dissolved in the drink.

Eliminate choices 1 and 2. Now focus on the temperature. Soda goes flat (loses carbonation or gas) as it warms up. Soda is usually served cold because more of the carbonation or CO2 stays in the drink when the soda is cold.

Hence, in high pressure and low temperature conditions gases are most soluble in water.

Lead caulked joints are used for laying Earthern ware pipes.

Earthenware is fired at 1900 degrees Fahrenheit, much lower than stoneware. The result is porous pottery that is not as strong as stoneware or porcelain pottery pieces and is cheaper than stoneware.

Giraffe has the highest blood pressure among animals. 

This is due to the fact that there is a large pressure drop (~100 mmhg) as the blood is transported from the heart, up the neck, to the brain. This is about twice the normal blood pressure of humans (120/80 mmhg).

(a) refers to political importance and (b) to economic importance. Out of (c) and (d), (c) is more important.

The US Congress consists of two bodies 

a) the Senate and   b) the House of Representatives. The Senate, composed of 100 members (two Senators from each State), is a powerful body and exercises a very real influence in national affairs.