The answer is D. High water pressure increases the speed of sound.
Explanation:
Due to the characteristics of seawater, the speed of sound propagation changes according to variations in temperature, salinity and pressure. The higher these water characteristics are, the higher their speed will be. if the pressure rises 10 atmospheres, when lowering 100 meters deep, the sound registers 1.8 meters per second of ascent.
In the early stages the embryos of four different species will look the same .For example, fish embryos and human embryos both have gill slits. In fish they develop into gills, but in humans they disappear before birth. That what makes them different.
