Host resistance typically works in what two main ways?

Host resistance primarily operates through the inherent traits of the host organism that enable it to withstand or repel pest attacks. The correct choice focuses on the presence of specific chemicals within the host plant that can deter pests or inhibit their development, as well as the development of more vigorous plant varieties that can thrive despite pest pressure.

Plants may produce secondary metabolites, such as alkaloids, terpenoids, or phenolics, that can be toxic or repellent to pests, thereby reducing the likelihood of pest infestations. Additionally, breeding programs often aim to develop more resilient varieties that exhibit enhanced growth, improved nutrient uptake, and greater tolerance to environmental stresses, allowing them to better survive pest attacks.

This method of host resistance is crucial in sustainable agriculture, as it reduces reliance on chemical pesticides and can lead to healthier ecosystems. The other options do not accurately encompass the primary mechanisms by which host resistance functions in managing pest populations.