The common component of air pollution is particulate matter (PM). This is a complex mixture of extremely small particles and liquid droplets.
The major components of PM are sulphates, nitrates, ammonia, sodium chloride, black carbon, dust particles and water. PM comes from dust , soot, smoke, industry and vehicle exhaust as well as complex chemical reactions with other pollutants.
Burning of fossil fuels produces sulphur dioxide . It is a colorless gas that pollutes the air and can cause health problems affecting the respiratory system.
Answer :There was enough oxygen in the atmosphere to support a major burst of life on Earth
Explanation:
The Great Oxygen Event marks the time, approximately 2.5 billion years ago, when there was enough oxygen in the atmosphere to support a major burst of life on Earth
For the first half of the Earht's history, there was no oxygen in the atmosphere. It was inhabited only by single-celled organisms.Of those simple life forms, the cyanobacteria may have. evolved a way to take energy from sunlight, and used it to make sugars out of water and carbon dioxide. They used the same chemical process we know as photosynthesis. This released vast quantities of oxygen into the atmosphere and triggered the evolution of complex life.
Answer:
Changes in gene expression
Explanation:
The correct answer is: a tourniquet.
The tourniquets are tight straps around an arm or leg and tightened to stop bleeding, used to control arterial and venous blood flow. In the past, tourniquet are used to control bleeding during amputations. Now, a tourniquet is used in surgeries to block arterial blood flow following and to minimize blood loss.
Alfred Russel Wallace, a biologist, naturalist and anthropologist who studied life in the tropics of Indonesia came up with the same idea of natural selection as Charles Darwin and prompted Darwin to publish his Origin of Specie sooner rather than later. He also studied the geographic distribution of species and as as well he was a social activist who criticized capitalism and warned of damage to the environment from man's economic activities.
