In an ecosystem,           

1.   cycling of energy and nutrients is a coupled process.

2.   cycling of energy is an independent process.

3.   movement of energy is unidirectional.

4.   both macro and micro consumers are necessary.

Choose the correct option for statement/s which complete/s the above statement.

• A

  only 1

• B

  only 3

• C

  1 and 3 both

• D

  only 4