Which of the following is a common characteristic of pests?

Pests are characterized by their potential to cause harm to crops and plants, which is why option B is the correct choice. Many pests, such as certain insects and weeds, can damage agricultural production, inhibit growth, and reduce the yield of crops, leading to significant economic losses for farmers and agricultural businesses. Understanding the detrimental effects of pests is crucial in pest management and control strategies, as their impact on food sources can also extend further to human populations.

While other options might suggest characteristics that do not typically apply to pests, such as benefiting the ecosystem, having no impact on human activities, or existing in small populations, they do not accurately reflect the common attributes associated with pests. For example, while some pests may serve ecological roles, their classification as pests arises from their harmful effects. Thus, recognizing that pests are primarily harmful to crops and plants helps highlight the need for effective pest management practices in agriculture.