Answer:
Osmosis
Step-by-step explanation:
As mentioned in the question,Pacific sea horse is an organism that face the constant challenge of losing water to their saltier environment. So if the environment is saltier it means that water will be moved from the Pacific horse' body cells into the environment to balance the concentration of salts. This process will happen when water molecules will move down the concentration gradient through selectively permeable membrane's of horse's body. This causes the loss of water from the body of horse and maintaining the salt levels of outside environment. This is called the process of Osmosis.
Here water move from an hypotonic environment (with less salts) into a hypertonic environment (with more salts).
Hope it helps!