a) Biogas: Biogas is the result of the controlled microbial breakdown of organic materials such as animal manures or food scraps in an anaerobic digester.Biogas is a mixture of about 60-70% methane (natural gas), 30-40% carbon dioxide and other trace gases, such as hydrogen sulfide.
b) Geothermal energy: The word geothermal comes from the Greek words geo (earth) and therme (heat). So, geothermal energy is heat from within the earth. We can use the steam and hot water produced inside the earth to heat buildings or generate electricity. Geothermal energy is a renewable energy source because the water is replenished by rainfall and the heat is continuously produced inside the earth.
c) Vaccine: Vaccine is an immunogen consisting of a suspension of weakened or dead pathogenic cells injected in order to stimulate the production of antibodies.
d) Antibiotic: Chemical substance formed as a metabolic by-product in bacteria or fungi and used to treat bacterial infections. Antibiotics can be produced naturally, using microorganisms, or synthetically.
e) Ceramics: Ceramics are classified as inorganic and nonmetallic materials that are essential to our daily lifestyle. This category of materials includes things like tile, bricks, plates, glass, and toilets.Ceramics are generally made by taking mixtures of clay, earthen elements, powders, and water and shaping them into desired forms. Once the ceramic has been shaped, it is fired in a high temperature oven known as a kiln. Often, ceramics are covered in decorative, waterproof, paintlike substances known as glazes.
f) Light year: A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 (km) each second. So in one year, it can travel about 10 trillion km. More precisely, one light-year is equal to 9,500,000,000,000 kilometers.