Answer:
Cultivated rice paddies
Drilling of natural deposits 
Fossil fuel use
Burning of biomass 
Landfills 
Step-by-step explanation:
The bulk of the methane released into the atmosphere are as a result of various human activities. 
- Cultivated rice paddies are a known source of methane
 - The drilling of natural deposits and their exploration can release some methane into the atmosphere
 - Burning of fossil fuel and biomass is a source of methane 
 - Landfills produces methane as organic materials begins to decay.