What are the three main characteristics of seawater that affect the speed of sound?

The correct answer is based on the fundamental physical properties of seawater that influence how sound travels through it. The three main characteristics that affect the speed of sound in seawater are temperature, salinity, and pressure.

Temperature directly impacts the speed of sound because warmer water allows sound waves to travel faster. As the temperature increases, the molecules move more rapidly, facilitating quicker propagation of sound waves.

Salinity also plays a critical role. Higher salinity increases the density of seawater, which can enhance the speed of sound. The chemical makeup of the water, particularly the amount of dissolved salts, alters how sound waves interact with the medium.

Pressure is important as well, particularly in deeper waters where the pressure is significantly higher. Increased pressure affects the density and elasticity of the water, leading to changes in the speed of sound.

Understanding these characteristics is crucial for various applications in marine navigation, sonar operation, and underwater acoustics. The other options listed do not accurately reflect the primary factors that influence the speed of sound in seawater, highlighting the specific role of temperature, salinity, and pressure in this context.