Why can fertile soil with poor drainage still be a problem for plants?

Correct answer: Because roots may face waterlogging and lack of air

Direct answer: Option B, roots may face waterlogging and lack of air. Fertile soil has nutrients, but healthy roots also need oxygen and a suitable amount of water. Step by step: poor drainage prevents extra water from leaving; water fills the spaces between soil particles; air is displaced; roots receive too little oxygen and may rot or absorb nutrients poorly; plant growth can then suffer even though the soil is fertile. Option A is wrong because nutrients are not always harmful; they are necessary in suitable amounts. Option B is correct. Option C is wrong because sunlight does not travel below soil in that way, and it is not the drainage mechanism. Option D is meaningless and unrelated to plant physiology; soil does not teach language. Exam cue: fertile soil is not automatically healthy soil—check drainage and aeration too.