Bacteria such as e. coli and salmonella produce invasins that bind host cells, thus causing the cells

a. engulf the bacteria.
b. produce iron-binding proteins.
c. release cytokines.
d. destroy the bacteria.
e. release tnf.

Option A.

Invasins cause the cell to engulf bacteria.

Explanation:

Invasins is an enzyme or protein that allow pathogens to penetrate into the host cells. Inavasins allow Salmonella to gain entry into the host cells and bind it to it thereby engulfing the bacteria during the stage of infection. Salmonella and E.coli produce invasins enzymesso as to penetrate the host cells and enqulf the bacteria.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."