Activation of muscle contraction could be a speedy event that's initiated by electrical activity within the surface membrane and transversal (T) tubules. This can be followed by unharness of metal<span> from the inner membrane system, the sarcoplasmic reticulum.
</span>Nervous stimulation causes a depolarization<span> of the muscle membrane (sarcolemma) </span>that<span> triggers </span>the discharge<span> of </span>calcium<span> ions from the sarcoplasmic reticulum.</span>
Answer: C). Sensory neurons, D).motor neurons
Explanation: Sensory neurons are nerve cells that carry signals from the external parts of the body such as the skin, eyes, ear, nose (the sense organs) to the brain.
Motor neurons are nerve cells that carry information or messages away from the central nervous system ( brain and spinal cord) to the rest of the body such as the skin, muscles and glands.
They are similar in three main ways
1.Both DNA and proteins are polymers.
2. Both are made from smaller subunits joined together. DNA is made of subunits called nucleotides joined together and protein is made up subunits called amino acids joined together.
3. In both of them, these subunits or monomers are linked together by covalent bonds.
Nucleotides are a combination of a nitrogen - rich base that is either adenine, guanine, cytosine or thymine, together with a phosphate group and a sugar.
The _Embryo_ is the answer
Hope this helps
