Pyroclastic materials are classified according to their size, measured in milli meters: dust (less than 0.6 mm [0.02 inch]), ash (fragments between 0.6 and 2 mm [0.02 to 0.08 inch]), cinders (fragments between 2 and 64 mm [0.08 and 2.5 inches], also known as lapilli), blocks (angular fragments greater than 64 mm), and bombs (rounded fragments greater than 64 mm).
The fluid nature of a pyroclastic flow is maintained by the turbulence of its internal gases. Both the incandescent pyroclastic particles and the rolling clouds of dust that rise above them actively liberate more gas. The expansion of these gases accounts for the nearly frictionless character of the flow as well as its great mobility and destructive power.
Pyroclastic flow, in a volcanic eruption, a fluidized mixture of hot rock fragments, hot gases, and entrapped air that moves at high speed in thick, gray-to-black, turbulent clouds that hug the ground. The temperature of the volcanic gases can reach about 600 to 700 °C (1,100 to 1,300 °F). The velocity of a flow often exceeds 100 km (60 miles) per hour and may attain speeds as great as 160 km (100 miles) per hour.
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The west Nile Virus is pathogen which caused the West Nile fever and encephalitis. The pathogen was introduced in 1999 in the Western Hemisphere and infected a major population in new york. It then expanded to 12 states and district of columbia. The major carrier of the pathogen was Avian and Mosquitoes species. In between 1999 to 2008, nearly 2500000 people were infected and nearly 1500 people died. Also there were thousands of cases of encephalitis or meningitis.
Answer:
The correct answer is option D. "whether the muscle moved the skeleton, the heart, or another type of internal organ".
Explanation:
It is possible to determine whether a sample of muscle tissue moved the skeleton, the heart, or another type of internal organ by analyzing its cellular structure and organization. For instance cardiac muscle is striated and organized into sarcomeres, while smooth muscle that is located in organs such as intestines, uterus and stomach are not organized into sarcomeres.
The process that lead to the formation of the distorted, wavy patterns found in metamorphic rock is regional metamorphism(as heat and pressure increases, minerals become segregated into bands).
