Decomposition in pools, ponds, and lakes takes place mostly in the zone.

a.

pelagic

b.

littoral

c.

benthic

d.

all of the above

The correct answer is C. benthic

This is a zone where there is no natural sunlight, meaning that the only source of energy is actually dead life forms that come from higher regions. That's why organisms from the benthic zone have a role in decomposition because they get their energy from other organisms.

343^x = 49^4-xx = 4-xx+x=42x = 4x = 4/2x = 2therefore x = 2