33. How do mangroves forest filter silt, dirt and sand from rivers?
A. The healthy leaves of mangroves block the particles.
B. The thick bark of, mangroves block particles from the land.
C. The numerous silts like roots of mangroves serve as filter for the particles.
D. The decayed, fallen leaves of mangroves block the sediments from reaching
the sea.
34. How does the human population affect the ecosystem?
A. Animals are covered
B. Forest are cleared to give way large subdivision
C. Plants and animals remain in the ecosystem
D. Plants are conserved for the need of the people​