Minerals and Nutrients

 Microelements in plants act as cofactors of enzymes.they are boron (B), chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), molybdenum (Mo), nickel (Ni).

Carbon is the most abundant element found in plants.Plants acquire carbon from the atmosphere through photosynthesis.

Among the following plant nutrients, calcium is a macronutrient. Rest other options are micronutrients.

 C, H, O and N are the most abundant elements in the living cells.

Deficiency of phosphorus causes premature leaf fall in plants. 

 Boron is useful in seed germination. It is also essential for seed and cell wall formation.

Among the options given, only sulphur is a macronutrient. Rest all are micronutrients.

Iron supplements contain soluble iron(II) salts to replenish them in the human body in case of deficiency. Iron supplements usually contain about 50mg per tablet of iron(II). Potassium manganate(VII), Mr = 158.034, is a good primary standard, being available to a high degree of purity, having a large relative mass and being stable in the environment thus it is used to determine the percentage of iron in the tablets by titration.

Sufficient amount of iodine is required by our body for maintaining a balanced mental status. 

Iodine (I) is found in thyroid hormones.

Element necessary for blood clotting is calcium (Ca).

Iron helps in energy metabolism.

The chemical compound calcium acetate is the calcium salt of acetic acid. It has the formula Ca(C₂H₃O₂)₂. In kidney disease, blood levels of phosphate may rise (called hyperphosphatemia) leading to bone problems. Calcium acetate binds phosphate in the diet to lower blood phosphate levels. Calcium acetate is used as a food additive, as a stabilizer, buffer and sequestrant, mainly in candy products. 

Calcium ions are essential for blood clotting, muscle contraction, nerve impulse transmission, and maintaining a regular heartbeat.

The human body is composed primarily of oxygen (approx 65%), followed by carbon (approx 18%), and nitrogen (approx 3%). Therefore, the descending order is oxygen, carbon, nitrogen, which corresponds to 1, 3, 2.