It has been a hot summer, so when you arrive at a lake, you decide to go for a swim even though it it nighttime. The water is cold. The next day, you go swimming again during the hottest part of the day, and even though the air is warmer the water is still almost as cold. Why? (a) Water is fairly dense compared with many other liquids.
(b) Water remains in a liquid state for a wide range of temperatures.
(c) Water has a high bulk modulus.
(d) Water has a high specific heat.

(d) Water has a high specific heat.

Explanation:

At night, when the temperature of earth goes down due to loss of heat , the temperature of water is lost slowly and temperature of land is lost fast because of high specific heat of water . Water loses as well as gains temperature comparatively slowly due to its high specific heat .

During daytime when earth gains heat , the temperature of land rises more rapidly than water so water appears cool even during daytime when land becomes  hotter . It is also due to high heat holding capacity of water or due to high specific heat of water .

a longitudinal wave moves energy that is to the direction of the wave’s movement. - true