The appearance of fossils would the the answer.
Although there has been some scientific debate about what fossil strata should mark the beginning of this period, the "International Geological Congress" determined that the Cambrian period was approximately 543 million years ago of which the first appearance in the fossil record of worms that made horizontal burrows was discovered.
Answer:
From smallest to largest:
Capillaries, alveoli, bronchi. bronchioles, trachea, pharynx, nasal cavity.
The presences of myelin allows an axon to conduct their signals rapidly
Answer:
The correct answer is a. absent spinal reflexes below the level of injury.
Explanation:
Spinal shock strictly refers to the neurological condition that occurs immediately after a spinal cord injury, in which the loss of not only motor and sensory functions occurs, but also the abolition of all reflexes below the injury (reflexes of muscular or myotatic stretching and cutaneous reflexes). There is also flaccidity, loss of reflexes. It is characterized by hypotension associated with cervical or upper thoracic spinal injuries. This characteristic shock results from the lesion of the descending sympathetic pathway in the spinal cord, producing a loss of vasomotor tone and sympathetic innervation of the heart. This causes vasodilation of the affected area with accumulation of blood and a decrease in venous return to the heart as well as cardiac output.
