 sulphur cycle, past the contents, importance of sulphur, reservoir of sulphur, mineralization, oxidation, reduction and incorporation of sulphur into organic compounds, and the diagrammatical representation of the sulphur cycle. First, the importance of sulphur, sulphur is also important like that of carbon, nitrogen, oxygen and fast-force. So, carbon, oxygen, nitrogen, or fast-force like sulphur is an important element. It is a component of different amino acids present in proteins. Proteins of different amino acids are important part, enzymes, because enzymes are very important in our life or in the living organisms, so enzymes, they are also having the sulphur in them. Then the vitamins, so these are the, if we are looking at it, the proteins have two amino acids in it, one is the methionine and the other one is the cysteine, so two sulphur containing amino acids and 20 amino acids in it, so they are having very important properties, so they have very important properties. So, it is abundantly present in the soil, so it is abundantly present in the soil, so it is abundantly present in the soil. So, the sulphur present in nature is present in the bright yellow crystalline form, bright yellow crystalline form is present in the pure form or in the compounds form. So, mostly it is buried under the rocks or rocks where it is buried or in the compound form. Some of the sulphur is also present in the atmosphere, in the form of different oxides of sulphur, like in the atmosphere when the sulphur dioxide is present, the oxides of the sulphur in the atmosphere actually represent a pollution, because if the sulphides are present, in the case of oxygen, sulphur oxides are present, the environment of sulphur oxides means that it is a pollution, it will have other effects in the acid rain. So, sulphur cycles are different steps, the first step is the mineralization. So, mineralization is the step in which organic sulphur is converted into sulphide or elemental surface sulphur. It is said that the organic sulphur is converted into inorganic form, that is, organic sulphur which is present in plants and animals, in proteins, that is converted into inorganic form. Inorganic form can be used, they are sulphides, sulphides can be an elemental surface or different minerals of sulphur can be used, sulphide minerals can be used. Second step is the oxidation of sulphides, the second step is the elemental surface, sulphur or sulphides are oxidized in the form of sulphates, so sulphides and elemental sulphur, elemental sulphur means pure sulphur will be oxidized and what will be made of it, sulphides will be made. So, next step, now the next step is how assimilation will be, how the sulphur will come in the body of plants and animals, so in this, the first sulphur, which is present in the sulphate form, so sulphides, what are the animals, they will reduce the sulphur in the form of, in the reduced form, so sulphide will be reduced first, after that they are made apart of the plant and animal body, so it will be made into part of the body of the plant and then the plants will reduce the sulphides and then the protein part or organic molecules will be made into part, so here is the cycle which is showing the overall sulphur cycle, here is the diagram which is representing the overall sulphur cycle, if we look at it, so first of all we talked that reduction is taking place, reduction means that the organic molecules will ultimately convert into reduced sulphur compounds, so reduced sulphur compounds will be converted into sulphates, these sulphates will be converted into sulphates, these sulphates they are utilized by the plants, they will reduce it and take it in the form of organic form, so the protein part will be made, then when the protein component is used, the sulphate will be made into part of the animal body, similarly when there will be the death of the plants or animals, then the decomposition process will take place and the decomposition process will be made into sulphates again, and some organic matter will be the one which will be converted into sulphate, some part of sulphur, some sulphur which will be present in the soil that is erupted along with the volcanic eruption, the volcanic eruption will be released from here and these will be the oxides of sulphur, sulphur dioxide or sulphur oxides will be released sulphur oxides will again be directed from the water of acid rain, and acid rain will be returned to the soil, but if we look at these, then the ecosystem will have a very bad impact on the plant life, it will die out, this is a simple example of how the sulphur is used in fossil fuels, so when the fossil fuels are used, then the sulphur will be released into the environment in the form of sulphur dioxide