AP BIOLOGY

Detailed explanation-1: -Nitrogen and phosphorous are critical determinants of plant growth and productivity, and both plant growth and root morphology are important parameters for evaluating the effects of supplied nutrients.

Detailed explanation-2: -Nitrogen frequently increases root growth and foraging capacity for phosphorus. Some of the effects of nitrogen are related to the effect on increasing the growth of plant tops and concurrently increasing the absorption of phosphorus.

Detailed explanation-3: -Plants absorb nitrogen from the soil as both NH₄⁺ and NO₃⁻ ions, but because nitrification is so pervasive in agricultural soils, most of the nitrogen is taken up as nitrate. Nitrate moves freely toward plant roots as they absorb water.