Which set of insects is beneficial to humans?

Consider the following statements about organic farming:
$I.$ Organic farming promotes the use of crop rotations and cover crops and encourages balanced host/predator relationships.
$II.$ Integrated pest and weed management and soil conservation systems are valuable tools on an organic farm.
$III.$ Organic farming protects the environment,minimizes soil degradation and erosion,and decreases pollution.
Which of the statements given above are correct?

Which plant is useful as green manure?

Which of the following is the full form of $IARI$?

Which chemical substance is used to remove unwanted weeds?

Which of the following is not economically useful?