"(1) as bob swam over the acropora reef, he couldn't help but notice the abundance of blue reef chromis
(1) a structure made by sessile marine invertebrates knows as corals, usually mostly by small polyped scleractinian corals such as acropora or montipora
""(1) as bob swam over the acropora reef, he couldn't help but notice the abundance of blue reef chromis" What is the definition of "reef"?