Answer:
A. The new evidence could be accepted and the theory changed.
Explanation:
most reasonable answer
Your answer is correct. Chitin provide the strength to insect exoskeletons. Cellulose is the strength for plant. Starch and glycogen are energy sources for life.
In the case of the muscular cramps, the muscle contraction starts with the generation of the action potentials from the brain. The action potential causes the release of the calcium ions movement out of the sarcoplasmic reticulum (storage site of calcium). The calcium released in this process causes the contraction of the myofibrils with the help of the ATP molecules. Meanwhile, the calcium is pumped back to the sarcoplasmic reticulum through the fast calcium pumps.
The contraction of one muscle cell generate the action potential in neighboring muscle cells. When the generation of the action potential is stopped, the sarcoplasmic reticulum relaxes as well as the muscle is relaxed. The fast calcium pump is powered by a sodium gradient, and the calcium influx is a result of fast outflux of the sodium ions from the sarcoplasmic reticulum.
In case, the sodium ion is less, the calcium pumps cannot be powered, the calcium ion would remain in myofibril, as a result, the muscle would be contracted for a longer time and this result in cramps. The muscle in this case, would be relaxed by the ATP instead of sodium gradient. So, it can be concluded that the muscle cramps are caused when the muscles are not able to relax properly.
Destruction of cells by viral reproduction.
Hope I helped!
Answer
→ to lose sensation,
→ motor control
Explanation:
Anatomically the spinal cord is made up of two roots, the Dorsal roots or the posterior roots where motor or efferent neuron leaves the spinal cord to innervate the skeletal muscles, trunks and the Ventral root or anterior roots where the afferent or sensory neuron convey input signals to the spinal cord from the the receptors.
Polio virus usually destroyed the nucleus of motor neurons, in the ventral roots of the spinal cord. its inflamed these cells, leading to death, The death leads to consequent degeneration at the site of inflammation, and progressive spread of this to other segments of the nerve fibre. This is called Wallerian Degeneration. Thus mechanisms of generation and transmission of action potential in these motor neuron is inhibited.
Consequently, motor output signals by the efferent neuron leaving through the dorsal roots is disrupted, and blocked . Thus effectors-muscles of limbs,trunks, are no longer innervated and stimulated, by efferent responses from the spinal cord and the brain, thus leading to loss of sensation and motor control.
With muscles redundancy, from lack of stimulation, muscles cells begin to waste away(muscle atrophy), and not able to control by the victim.This is paralysis.
