An operculus covers which body part of a bony fish?

the gills                       is the answer

scientists have discovered that hiv does not cause aids by the virus's direct effect on the host's immune cells, but rather through the cells' lethal influence on one another. researchers from the gladstone institutes have revealed that hiv does not cause aids by the virus's

because they are eaten by the frog and the frog getseaten by the snake and the snake by the eagle