Which statement is true?

Which statement is true?

• A. Resistant plants do not readily become infected by a specific disease unless environmental factors are extremely favorable
• B. Resistant varieties resist all diseases common to the species
• C. A plant variety bred for specific disease resistance will never get that disease
• D. Once exposed to a disease, resistant plants can develop immunity much like animals do

Answer: (A)

Plants don’t fall into a simple on/off immunity with diseases. The main idea here is that resistance lowers the chance of infection and curbs disease development, but it isn’t absolute. A plant variety that is resistant to a particular disease will still be susceptible if environmental conditions strongly favor the pathogen—things like high humidity, warm temperatures, or heavy inoculum can overcome resistance and lead to infection or noticeable symptoms. That’s why the statement describing resistance as reducing infection risk unless conditions are extremely favorable is the true one. Resistance is typically partial and often specific to certain pathogens or races; it doesn’t guarantee that a plant will never get the disease. The idea that resistant varieties resist all diseases common to the species is incorrect because no single resistance gene covers every possible pathogen. Likewise, the notion that a bred variety will never get the disease, even with specific resistance, is misleading for the same reason. And plants don’t develop immunity in the same way animals do; while they can mount defense responses, resistance isn’t a form of true immunity that prevents infection after exposure.

Plants don’t fall into a simple on/off immunity with diseases. The main idea here is that resistance lowers the chance of infection and curbs disease development, but it isn’t absolute. A plant variety that is resistant to a particular disease will still be susceptible if environmental conditions strongly favor the pathogen—things like high humidity, warm temperatures, or heavy inoculum can overcome resistance and lead to infection or noticeable symptoms. That’s why the statement describing resistance as reducing infection risk unless conditions are extremely favorable is the true one.

Resistance is typically partial and often specific to certain pathogens or races; it doesn’t guarantee that a plant will never get the disease. The idea that resistant varieties resist all diseases common to the species is incorrect because no single resistance gene covers every possible pathogen. Likewise, the notion that a bred variety will never get the disease, even with specific resistance, is misleading for the same reason. And plants don’t develop immunity in the same way animals do; while they can mount defense responses, resistance isn’t a form of true immunity that prevents infection after exposure.