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b-false.
17-low marshes are : a-more productive than high marshes.
b-less productive than high marshes.
18-plants of salt marshes : a- are grazed by different kinds of
herbivorous.
b-none of these plants is grazed by animals.
19-salt marshes : a- are affected by Human activities.
b-are not affected by Human activities .
20-the mangrove : a- is a large woody, treelike plant that grow in
muds.
b-is a rootless plant that float on the surface of water.
21-the mangove : a- has a network of intertwinted roots called proproots.
b-has few separated roots that are attached to the bottom of the sea.
22-Mangrove swamps support : a- an abundant and diverse fauna.
b-only few species of invertebrates.
23-there are some physical and chemical factors that affect the
distribution and density of species in mangrove swamps : a- true.
b-false.
24-the mangrove ’s leaves : a- fall at a rate faster during the summer
than during other times.
b-fall at a rate faster during the winter than during other times.
25- dead leaf biomass is consumed by detritivors : a-true.
b-false.
26-peat : a- is a richly organic soil of partially decomposed
vegetation.
b-a substance added to soil to make plants grow more successfully.