. Chemical substances rich in specific nutrients are called
A:Manures - Manure is the degraded form of dead plants and animals that is spread on the soil to boost productivity.
B:Fertilizers - Fertilizers are nutrient-rich chemicals, that farmers employ to add nutrients to the soil on their farms.
C:Pesticides - Any substance or combination of compounds used to prevent, eliminate, repel, or mitigate pests.
D:Weedicides - Weedicides are chemicals that are sprayed across fields to kill weeds.
Hence, the correct answer is B, fertilizers.