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Chronic back strain occurs because of the sustained trauma and wearing out of the back muscles. [1] Acute back strain can occur following a single instance of over stressing of back muscles, as in lifting a heavy object. Chronic back strain is more common than the acute type. To avoid back strain it is important to bend the knees whenever you ...
The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth's history, a time span of about 4.54 ± 0.05 Ga (4.54 billion years). [3] It chronologically organises strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or ...
The Precambrian includes approximately 90% of geologic time. It extends from 4.6 billion years ago to the beginning of the Cambrian Period (about 539 Ma).It includes the first three of the four eons of Earth's prehistory (the Hadean, Archean and Proterozoic) and precedes the Phanerozoic eon.
The lumbar region is sometimes referred to as the lower spine, or as an area of the back in its proximity. In human anatomy the five lumbar vertebrae (vertebrae in the lumbar region of the back) are the largest and strongest in the movable part of the spinal column , and can be distinguished by the absence of a foramen in the transverse process ...
Approximately 9–12% of people (632 million) have low back pain at any given point in time, [26] and nearly 25% report having it at some point over any one-month period. [7] [8] About 40% of people have low back pain at some point in their lives, [7] with estimates as high as 80% among people in the developed world. [27]
If you’re struggling with an achy back and could therefore benefit from some lower back stretches, you’re not alone: Lower back pain impacted an estimated 619 million people around the world ...
The first eon in Earth's history, the Hadean, begins with the Earth's formation and is followed by the Archean eon at 3.8 Ga. [2]: 145 The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga, [34] [35] [36] soon after the formation of the Earth's crust and the Earth
This species might be evolved some time before, up to c. 2 Ma ago. c. 1.7 Ma – Australopithecines go extinct. c. 1.8–0.8 Ma – colonisation of Eurasia by Homo erectus. c. 1.5 Ma – earliest possible evidence of the controlled use of fire by Homo erectus; c. 1.2 Ma – Homo antecessor evolves. Paranthropus dies out.