Consider the following four statements about wetland ecosystems:
a. They are the transitional zones between terrestrial and aquatic ecosystems.
b. They are highly productive.
c. They are the source of greenhouse gases.
d. They normally occur in the floodplain of rivers.
Choose the correct answer:
1
a and b only
2
a, b, and c only
3
b, c, and d only
4
a, b, c, and d