the answer is 21<span>% oxygen, </span>
It influences the rates at which organisms grow and reproduce.
Answer:
Reflex action is the sudden uncontrolled reaction towards a certain stimuli eg response to hot iron
Reflex arc is the path taken by reflex action to a certain stimuli
Diagram depends to
Receptor(eg skin), receptor nerve(sensory neurone),centre reflex arc(spinal cord most of reflex action) they met relay neurone, motor neurone and ends at reflexor (eg muscle)
The nervous system and the muscle system respond to stimuli to produce motion. The skeletal movements of muscles are mostly voluntary.
Involuntary movements occur in these muscles when the nerve impulse passes from a sensory neuron to a motor neuron via an interneuron in the spinal cord.
<h3>What are Skeletal muscles?</h3>
Skeletal muscles may be defined as the muscles that fasten to your bones and authorize you to achieve a broad range of activities and operations.
Skeletal muscles control the direct movement of a person's will and are hence referred to as voluntary movement. While the spinal cord is associated with both movements directly or indirectly. It is a prolonged, delicate tubelike network liable for holding incoming and outgoing messages through the brain to the rest body.
Therefore, it is well described above.
To learn more about Involuntary movements, refer to the link:
brainly.com/question/1462286
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<em>A megaphone used by a cheerleader can allow people on the opposite side of a field to hear her better because;</em>
D. Solid objects can change the direction of sound waves; megaphones allow users to determine the general direction of the sound.
<u>Determination of the general direction of the sound lessens its dispersion and thus, it reaches the observers at a higher intensity, hence it being louder.</u>
