A spasm is a sudden, involuntary contraction of a muscle, a group of muscles, or a hollow organ such as a heart, or a similarly sudden contraction of an orifice.It most commonly refers to a muscle cramp which is often accompanied by a sudden burst of pain, but is usually harmless and ceases after a few minutes. spasm is a sudden, involuntary contraction of a muscle, a group of muscles, or a hollow organ such as a heart, or a similarly sudden contraction of an orifice.
Top 10 largest Cement Producing Countries in the World. China has the first stage in the list of cement producing countries. They produce more than 2482 million tonnes. It is mainly used for construction and china is highly populated.
Today, PetroChina is one of the world's largest companies by market capitalization. It is also China's largest producer of oil and natural gas. Last year, the company's output from production included 932.9 million barrels of oil, as well as 2.8 trillion cubic feet of natural gas.