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  Sulphur cycle :  The cycling of sulphur between biotic and abiotic systems is called sulphur cycle. It is a sedimentary cycle .  Sulphur is an important component of proteins and amino acids. Sulphur exists in a number of states. Of these, three are important. They are elemental sulphur, sulphides and sulphates. Sulphur is present in rocks. It is made available for plants in the form of inorganic sulphate by weathering and erosion. Sulphur passes into the animals through food chain. By the death of plants and animals, the decomposers again bring the sulphur to the soil for the use of plants. Some sulphur in dead bodies is released into the air as hydrogen sulphide  ( H 2 S )  by the bacteria called  Escherichia coli  under anaerobic combustion. Similarly incomplete combustion of fossil fuel releases sulphur dioxide   ( S O 2 )  into the air. Certain bacteria (green and purple photosynthetic bacteria) oxidise  H 2 S of air to sulphate which can be used by plants.

Hello friends this is   Aarif Meo here and welcome to CREST SCIENCE ACADEMY Dear friends we are going to start FROM FIRST JANUARY 2020  our all social platform qwith weasy good and excllent snote with videos and pdf file we are going to spread mess for all to get first join free of cost  As you know dear students and friends the CREST SCIENCE ACADEMY   is created to spread the knowledge of Life Science and Biology by sharing all this free education of   biology lectures video and animation presented by great and experienced faculty   here on   YouTube. All these tutorials are brought to you for free. Please subscribe to our channel so that we can grow together. This centre will help in CSIR-NET/JRF, ICMR-NET/JRF, GATE LIFE SCIENCE,   and GATE BIOTECH, DBT, IISc, M.Sc and P.Hd in Life Science entrance exam. This centre is also for the NEET/AIIMS /JIPMER and many more exam medical science.   You can check for any of the following services from Crest Science Academy. Find u

The environment is the aggregate of all those things and set of conditions which directly or indirectly influence not only the life of organisms but also the communities at a particular place. Any external force or influence, which surrounds and affects the life of a plant in any way, becomes a factor of its environment. These factors are called environmental factors and may be living (biotic) as well as non-living (abiotic). The abiotic factors affect the structure, life history, physiology and behaviour of organisms. The biotic factors mostly influence growth and reproduction. The environmental conditions which influence the life and development of plants, each part of the environment is called ecological factors. Ecological factors are grouped into four main classes (ecological factors) which are as follows : Climatic factors :  The study of climatic factor is known as climatology. The chief climatic factors are : (1)  Water :  Rainfall is the chief source of soil moisture. Wa