Answer:
when a person has aids they usually start coughing up blood
Explanation:
The most important factor which determines whether the living things can survive in a body of water s its salinity. The salinity level of the water is the factor at play in deciding which of the living organisms live inside the water. The salinity of the organisms has to be similar to the salinity level of the water in order for them to survive, otherwise, they will be dehydrated as a result of osmosis.
Hence, the answer is 'salinity'.
