Match the following:

1-B, 2-D, 3-A, 4-C

Mini-hydel plants use the energy of perennial streams to move small turbines. 

Earthworms can convert organic matter into compost faster than the normal composting process.

In order to control the pests various animals and birds help. For example: snakes, lizards etc. These birds and animals prey upon pests and insects and help in pest control. 

Organic farming use organic inputs for cultivation. It discards the use of chemical inputs.