Answer:
Climate.
Step-by-step explanation:
Climate is the factor which is responsible for the decreasing the availability of crops because climate is the factor that allows crops to grow in the region. Suitable climatic conditions allows us to grow more plants in the region while on the other hand, less or no crops can be cultivated in the harsh climatic conditions. The plants in the harsh climatic condition are unable to grow such as desert where the temperature is very high and no rainfall occurs to support growing of crops.