Which statement about weeds is NOT true?

The statement that weeds enhance the growth of agricultural crops is not true. Weeds often compete with crops for essential resources such as light, water, and nutrients, which can hinder crop growth and reduce agricultural productivity. They can create an adverse environment for crops by overshadowing them and exhausting the soil's resources, leading to lower yields.

Conversely, the other statements highlight actual issues associated with weeds. Weeds can reduce biological diversity by outcompeting native plants, disrupt ecosystems, and negatively impact wildlife. Certain weeds can endanger livestock by being toxic or providing breeding ground for harmful pests. Additionally, weeds can obstruct the safe use of rights-of-way, such as roads and pathways, by causing visibility issues and creating hazards. Overall, while there are some ecological roles that some weeds can play, the idea that they enhance crop growth contradicts the common challenges they present in agriculture.