What are bacteria primarily responsible for?

Bacteria play a significant role in various ecological and biological processes, making them vital in both the natural world and human activities. They are primarily responsible for food decay and diseases affecting plants and animals.

When it comes to food, bacteria can decompose organic matter, breaking down complex compounds into simpler substances. This activity is crucial in natural ecosystems, where it recycles nutrients, but it also leads to the spoilage of food products. This decay can cause food to become inedible, posing challenges for food safety and preservation.

In agriculture, certain bacteria can infect plants, leading to diseases that can severely impact crop yields. Similarly, pathogenic bacteria can infect animals, causing illnesses that can affect livestock health and, by extension, food supplies for humans.

While bacteria also contribute positively in various ways, such as improving soil fertility through the nitrogen cycle or aiding in the production of antibiotics, the broader scope of their impact includes both beneficial and harmful aspects. The correct option accurately captures the duality of bacterial roles in decaying food and causing diseases, emphasizing their significant presence in these domains.