Thermocline - <span>a steep temperature gradient in a body of water, that is marked by a layer above and below at which the water is at different temperatures.
halocline - </span><span> a subtype of chemocline caused by a strong, vertical salinity gradient within a body of water.
pycnocline - </span><span>a layer in an ocean or other body of water in which water density increases rapidly with depth.</span>
        
             
        
        
        
A parasite moving between individuals other than parents and their offspring uses 
horizontal transmission.
Horizontal transmission is the transmission of infections between (parasites) that are not in a parent-child relationship (vertical transmission). Horizontal transmission may include the carriers or <span>vectors which are other species. Transmission, in that case, occurs via the bite of the vector (an infected organism), like in malaria.</span>
 
        
        
        
1. B. 2.B 3.C. 
1. Fossils is a main supporter of the evolution theory 
2. Evolution 
3. Lack oh adaptation risk death