Duckweed consists of tiny, free-floating green plants. duckweed typically consists of a leaf or cluster of leaves with small roots that hang down into the water; leaves and stem are not distinguishable from each other. it occurs on the surface of ponds, inlet creeks, and ditches. it and can exist as floating mats on the water's surface. which of these accurately describes the likely effect that duckweed has on the submerged plant populations in the lakes where duckweed is found?