B-A 



BACTERIA 



Microscopic, single-celled or noncellular 

 plants, usually saprophytic or parasitic. 



BARRIER BEACH 



A ridge of deposits separated from the 

 mainland by an interval of water. 



BARRIER REEF 



Large, thick, coral mass more or less 

 surrounding an island or paralleling the 

 mainland shore in tropical areas; separated 

 from the land mass by a lagoon. (See Atoll , 

 Fringing Reef ) 



BATHYAL ZONE 



That region of the sea that extends from the 

 euphotic zone to the bottom of the continental 

 slope . Density of life in this zone depends 

 on organic material settling from the euphotic 

 zone and is generally inversely proportional 

 to the depth. 



BEACH 



The zone of demarcation between land and water 

 of lakes, seas, etc.; covered by sand, gravel 

 or larger rock fragments. 



BENTHIC REGION 



The bottom of a waterway; the substratum that 

 supports the benthos . 



