Which of the following organisms is considered beneficial to plants?

Spiders are considered beneficial to plants primarily because they are natural predators of various pests that can harm plants. They actively hunt and consume insects such as aphids, thrips, and other harmful pests, thereby helping to manage pest populations and reduce the need for chemical pest control methods. This predatory behavior contributes to a healthier ecosystem within the garden or agricultural system, enabling plants to thrive with less competition from harmful pests.

In contrast, thrips, moths, and spittlebugs can have detrimental effects on plants. Thrips can damage plant tissues and spread diseases, moths often have larvae that feed on foliage, and spittlebugs can weaken plants by feeding on sap, causing stress and potential decline in plant health. Therefore, while some organisms may play roles in the ecosystem, spiders stand out as direct beneficial contributors to the health of plants by controlling pest populations.