AP BIOLOGY

Detailed explanation-1: -Among the micronutrients, Fe, Mn, Cu, Zn, and Ni are taken up by plants in their cationic forms, and B, Mo, and Cl are taken up by plants in their anionic forms. Fe and Mn are often present in large quantities in most soils, and adsorption reactions play little role in controlling their plant availability in soils.

Detailed explanation-2: -Common contaminants in urban soils include pesticides, petroleum products, radon, asbestos, lead, chromated copper arsenate and creosote. In urban areas, soil contamination is largely caused by human activities.

Detailed explanation-3: -We’ve established that plants need carbon dioxide (CO2) and water (H2O) to produce their food, but where do these reactants come from and how do they get where they need to go inside the plant? Plants take in carbon dioxide from the air through small openings in their leaves called stomata.

Detailed explanation-4: -For the present purposes, plant chemicals will be considered under three main biogenetic classes: terpenoids, alkaloids and related nitrogen compounds and phenolics.

Detailed explanation-5: -Certain chemicals are known to stimulate plant growth and yield. Many growth regulators also increase the protein content of plants. Treatment with pesticides and herbicides may also change the nutritive quality.