What part of the plant do nematodes attack?

Nematodes primarily target the roots of plants, making this the correct answer. These microscopic roundworms inhabit the soil and can invade the root systems of various plants. Once inside, they can cause significant damage by disrupting the plant's ability to absorb water and nutrients effectively. This can lead to stunted growth, wilting, and ultimately plant death if the infestation is severe.

In contrast, while leaves, flowers, and stems are essential parts of the plant, they are not the typical targets for nematode damage. Nematodes specifically focus on the root zone where they can penetrate and establish feeding sites, as these areas provide them with the nutrients necessary for their growth and reproduction. Understanding the specific targets of pests like nematodes is crucial for effective management and control strategies in agriculture.