Essential Mineral Elements

Answer (d) Molybdenum

Carbon is the most abundant element present in the plant. Other framework elements are hydrogen and oxygen.

Azospirillum is an anaerobic nitrogen fixing bacteria which forms loose association with roots of some plants. Inoculation of paddy fields with these bacteria helps in increasing yield and saving of nitrogen fertilizers.

The correct option (D): Senescent leaves .

Oxygen is evolved during photosynthesis by the process of photolysis of water taking place in the membranes of grana thylakoids. The phenomenon of breaking up of water into hydrogen and oxygen in the illuminated chloroplasts is called photolysis or photocatalytic splitting of water. Light energy, an oxygen evolving complex (OEC) and electron carrier Yz are required for this process. Oxygen evolving complex is attached to the inner surface of thylakoid membrane and the enzyme has four Mn ions. Light energised changes in Mn (Mn{2+}, Mn{3+}, Mn{4+}) remove electrons from OH- component of water forming oxygen. Liberation of O2 also requires two other ions, Ca2+ and Cl-