C. Some waves travel as transverse waves, but there are also longitudinal waves.
The propagation velocity of the waves depends on density and elasticity of the medium. Velocity tends to increase with depth and ranges from approximately 2 to 8 km/s in the Earth's crust up to 13 km/s in the deep mantle.
Answer:
These organelles are contractile vacuoles
Explanation:
Contractile vacuoles are intercellular pumps that are slowly filled with fresh water and eventually expel their contents outside the cell. Freshwater protists maintain the hydric equilibrium by contractile vacuoles that pump out the water of the cell and thus prevent the cell swelling induced by osmotic stress.