An organism that exhibits a head with sensory equipment and a brain probably also have receptors, which capture the stimuli of the environment and transform them into a nervous impulse, and organs of the senses that are the communication channels we have with the environment and thanks to them we understand and interpret the environment, they are: vision, hearing, smell, taste, and touch.
Salinity and density share a positive relationship. As density increases, the amount of salts in the water—also known as salinity, increases. Various events can contribute to change in the density of seawater. Salinity can decrease from the melting of polar ice or increase from the freezing of polar ice.